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ScienceQA

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Which of the following contains a vague pronoun reference?

closed choice

grade11

language science

writing-strategies

Pronouns

Identify vague pronoun references

When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent. When Lisa and Kim finally landed, she breathed a sigh of relief. The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear. Vague pronoun references can be corrected in one of two ways: 1. Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief. 2. Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed. A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent. They say that this nail polish dries in less than five minutes. The pronoun they is used without its antecedent, so the meaning of the sentence is unclear. This problem can be fixed by replacing the pronoun with its missing antecedent. The advertisements say that this nail polish dries in less than five minutes.

The second answer choice contains a vague pronoun reference. The pronoun them could refer to the new employees or their intake forms. The first answer choice shows a possible correction for the vague pronoun reference. Them has been replaced with the forms. Mr. Hammond wanted the new employees to fill out their intake forms, but he couldn't find the forms.

Which word would you find on a dictionary page with the following guide words? terrify - trousers

closed choice

grade6

language science

reference-skills

Reference skills

Use guide words

Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.

Put the words in alphabetical order. Since theme is between the guide words terrify - trousers, it would be found on that page.

What is the volume of a water pitcher?

Select the best estimate.

closed choice

grade4

natural science

units-and-measurement

Units and measurement

Choose customary units of volume

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Volume is a measurement of how much space something takes up. There are many different units of volume. When you are using customary units, volume may be written in units of fluid ounces, cups, or gallons. As the diagram shows, there are 8 fluid ounces in 1 cup and 16 cups in 1 gallon. So, 1 fluid ounce is less than 1 cup and much less than 1 gallon. A glass of milk has a volume of about 8 fluid ounces, or 1 cup. A jug of milk has a volume of 1 gallon.

The best estimate for the volume of a water pitcher is 10 cups. 10 fluid ounces is too little and 10 gallons is too much.

Which greeting is correct for a letter?

closed choice

grade4

language science

punctuation

Formatting

Greetings and closings of letters

A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory

The second greeting is correct: Its first word is capitalized, and it ends with a comma. Uncle Ron is capitalized because it is a proper noun.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.

closed choice

grade4

natural science

physics

Magnets

Compare strengths of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the strength of a magnetic force between two magnets by changing the distance between them. The magnetic force is stronger when the magnets are closer together.

Distance affects the strength of the magnetic force. When magnets are closer together, the magnetic force between them is stronger. The magnets in Pair 1 are closer together than the magnets in Pair 2. So, the magnetic force is stronger in Pair 1 than in Pair 2.

Is there a sentence fragment? During the Precambrian period, most of Earth's life forms lived in oceans. Meanwhile, land masses were mostly devoid of life.

yes or no

grade12

language science

writing-strategies

Sentences, fragments, and run-ons

Identify sentence fragments

A sentence is a group of words that expresses a complete thought. The band I'm in has been rehearsing daily because we have a concert in two weeks. A sentence fragment is a group of words that does not express a complete thought. Rehearsing daily because we have a concert in two weeks. This fragment is missing a subject. It doesn't tell who is rehearsing. The band I'm in. This fragment is missing a verb. It doesn't tell what the band I'm in is doing. Because we have a concert in two weeks. This fragment is missing an independent clause. It doesn't tell what happened because of the concert.

There is not a sentence fragment. These are complete sentences because they express complete thoughts. During the Precambrian period, most of Earth's life forms lived in oceans. Meanwhile, land masses were mostly devoid of life.

Which property matches this object?

Select the better answer.

closed choice

grade2

natural science

physics

Materials

Identify properties of an object

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.

Look at the object. Think about each property. A shiny object reflects a lot of light. The bracelet is shiny. A scratchy object is rough and itchy against your skin. The bracelet is not scratchy.

Would you find the word easily on a dictionary page with the following guide words? edge - envy

yes or no

grade7

language science

reference-skills

Reference skills

Use guide words

Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.

Put the words in alphabetical order. Since easily is not between the guide words edge - envy, it would not be found on that page.

Which is a simple sentence?

closed choice

grade3

language science

grammar

Sentences, fragments, and run-ons

Is the sentence simple or compound?

A simple sentence is a sentence with only one subject and predicate. The pitcher threw the ball to first base. A compound sentence is two simple sentences joined by a comma and a conjunction such as and, but, or, or so. The pitcher threw the ball, and the batter hit it. Some simple sentences have a compound subject or a compound predicate, but they are not compound sentences. Anna and James will watch the fireworks tonight. This simple sentence has a compound subject, Anna and James. The singers bowed and walked off the stage. This simple sentence has a compound predicate, bowed and walked off the stage. Some simple sentences have introductory phrases, but they are not compound sentences. The introductory phrase is part of the predicate. In the winter, Farmer Ben wears his heavy coat. This is a simple sentence. There is one subject, Farmer Ben, and one predicate, wears his heavy coat in the winter.

The first sentence is the simple sentence. It has one subject and predicate. The engine in the car makes a strange noise.

Select the fish below.

Fish live underwater. They have fins, not limbs. Fish are cold-blooded. The body temperature of cold-blooded animals depends on their environment. A goldfish is an example of a fish.

closed choice

grade4

natural science

biology

Classification

Identify mammals, birds, fish, reptiles, and amphibians

Birds, mammals, fish, reptiles, and amphibians are groups of animals. Scientists sort animals into each group based on traits they have in common. This process is called classification. Classification helps scientists learn about how animals live. Classification also helps scientists compare similar animals.

A fire salamander is an amphibian. It has moist skin and begins its life in water. Fire salamanders can release poison from their skin. This poison helps protect them from predators. A penguin is a bird. It has feathers, two wings, and a beak. Penguins live near water. Penguins cannot fly! They use their wings to swim. A woodpecker is a bird. It has feathers, two wings, and a beak. Woodpeckers have strong beaks. They use their beaks to drill into wood to hunt for food. A green moray eel is a fish. It lives underwater. It has fins, not limbs. Eels are long and thin. They may have small fins. They look like snakes, but they are fish!

Identify the question that Eliana and Dean's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Eliana applied a thin layer of wax to the underside of her snowboard and rode the board straight down a hill. Then, she removed the wax and rode the snowboard straight down the hill again. She repeated the rides four more times, alternating whether she rode with a thin layer of wax on the board or not. Her friend Dean timed each ride. Eliana and Dean calculated the average time it took to slide straight down the hill on the snowboard with wax compared to the average time on the snowboard without wax. Figure: snowboarding down a hill.

closed choice

grade8

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

What can Stefan and Bruce trade to each get what they want?

Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another. Stefan and Bruce open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Stefan wanted broccoli in his lunch and Bruce was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

closed choice

grade6

social science

economics

Basic economic principles

Trade and specialization

Stefan wanted broccoli in his lunch and Bruce was hoping for tomatoes. Look at the labeled part of the images. Stefan has tomatoes. Bruce has broccoli. They can trade tomatoes for broccoli to both be happier. Trading other things would not help either person get more items they want.

Which statement describes the Gobi Desert ecosystem?

Figure: Gobi Desert. The Gobi Desert is a cold desert ecosystem located in northern China and southern Mongolia. This desert is next to the Himalayan Mountains and used to be part of the Mongol Empire.

closed choice

grade5

natural science

biology

Ecosystems

Describe ecosystems

An environment includes all of the biotic, or living, and abiotic, or nonliving, things in an area. An ecosystem is created by the relationships that form among the biotic and abiotic parts of an environment. There are many different types of terrestrial, or land-based, ecosystems. Here are some ways in which terrestrial ecosystems can differ from each other: the pattern of weather, or climate the type of soil the organisms that live there

A cold desert is a type of ecosystem. Cold deserts have the following features: a small amount of rain or snow, dry, thin soil, and long, cold winters. So, the following statements describe the Gobi Desert ecosystem: a small amount of rain or snow, dry, thin soil, and long, cold winters. It has long, cold winters. It has dry, thin soil. The following statement does not describe the Gobi Desert: a small amount of rain or snow, dry, thin soil, and long, cold winters. It has year-round snow.

As the wind pushes on the kite, what is the direction of the opposing force?

The text below describes a pair of opposing forces. Opposing forces act on an object in opposite directions. Read the text. Then answer the question below. Lexi flies a kite on a windy day. She uses a string to hold on to the kite. Think about two of the forces that act on the kite: The wind pushes away from Lexi. The string pulls toward Lexi.

closed choice

grade3

natural science

physics

Force and motion

How do balanced and unbalanced forces affect motion?

A force is a push or a pull that acts on an object. Each force acts on an object in a certain direction. If two forces act on an object in opposite directions, they are called opposing forces.

Find the direction the wind pushes on the kite. Lexi flies a kite on a windy day. She uses a string to hold on to the kite. Think about two of the forces that act on the kite: The wind pushes away from Lexi. The string pulls toward Lexi. The text tells you that the wind pushes away from Lexi. The opposite direction is toward Lexi. So, the direction of the opposing force is toward Lexi.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade8

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

Each particle in sample A has more mass than each particle in sample B. The particles in sample A also have a higher average speed than the particles in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

Which announcement is more formal?

closed choice

grade9

language science

writing-strategies

Audience, purpose, and tone

Which text is most formal?

Informal writing is typically used in casual situations or when communicating with someone you know well. Informal language often expresses familiarity and tends to sound more like speech. It uses more conversational language, such as slang, idioms, abbreviations, imprecise language, and contractions. Formal writing is typically used in academic and business writing or when writing directly to an authority figure. It tends to be more courteous and impersonal, avoiding overly familiar or conversational language. Compare the following sentences. Informal: Yeah, ostriches can't fly, but I think they're awesome. More formal: Ostriches may be flightless, but they're remarkable runners. Most formal: Though flightless, ostriches are remarkable runners.

The first announcement is more formal. It uses more elevated language (pleased to announce). The other announcement sounds more conversational (so happy).

Which object has the most thermal energy?

The objects are identical except for their temperatures.

closed choice

grade4

natural science

physics

Heat and thermal energy

How is temperature related to thermal energy?

All solids, liquids, and gases are made of matter. Matter is made up of tiny particles that are always moving. The energy from the motion of these particles is called thermal energy. Temperature measures how hot or cold matter is. If the particles in matter move faster, the temperature goes up. The matter now has both more thermal energy and a higher temperature.

All three cups of black tea have the same mass but different temperatures. Since the 62°C cup of black tea is the hottest, it has the most thermal energy.

Identify the question that Duncan's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Duncan put one two-inch steel nail into each of six test tubes. He added water to three of the test tubes and vinegar to the other three. In each test tube, he completely covered the nail with the same volume of liquid. Duncan checked the nails for rust at the same time every day. He recorded how many days it took each nail to become completely covered in rust. Then, he compared the number of days it took nails to rust in water to the number of days it took nails to rust in vinegar. Figure: a new steel nail on a pile of rusty nails.

closed choice

grade6

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

Which better describes the tide pool ecosystems in Salt Point State Park?

Figure: Salt Point State Park. Salt Point State Park is in northern California. The park is on the coast of the Pacific Ocean. It has many tide pool ecosystems.

closed choice

grade3

natural science

biology

Ecosystems

Describe ecosystems

An ecosystem is formed when living and nonliving things interact in an environment. There are many types of ecosystems. Here are some ways in which ecosystems can differ from each other: the pattern of weather, or climate the type of soil or water the organisms that live there

A tide pool is a type of ecosystem. Tide pool ecosystems have the following features: daily flooding and draining of seawater, water that is rich in nutrients, and many different types of organisms. So, the tide pool ecosystems in Salt Point State Park have water that is rich in nutrients. They also have many different types of organisms.

What is the capital of Idaho?

closed choice

grade5

social science

geography

State capitals

Identify state capitals of the West

Boise is the capital of Idaho.

What is the probability that a pea plant produced by this cross will be homozygous recessive for the pod shape gene?

This passage describes the pod shape trait in pea plants: Pea plants protect their seeds in pouch-like cases called pods. Some pea plants grow inflated pods, which are smooth. Other pea plants grow constricted pods, which are bumpy. In a group of pea plants, some individuals have inflated pods and others have constricted pods. In this group, the gene for the pod shape trait has two alleles. The allele for inflated pods (D) is dominant over the allele for constricted pods (d). This Punnett square shows a cross between two pea plants.

closed choice

grade8

natural science

biology

Genes to traits

Use Punnett squares to calculate probabilities of offspring types

Offspring genotypes: homozygous or heterozygous? How do you determine whether an organism is homozygous or heterozygous for a gene? Look at the alleles in the organism's genotype for that gene. An organism with two identical alleles for a gene is homozygous for that gene. If both alleles are dominant, the organism is homozygous dominant for the gene. If both alleles are recessive, the organism is homozygous recessive for the gene. An organism with two different alleles for a gene is heterozygous for that gene. In a Punnett square, each box represents a different outcome, or result. Each of the four outcomes is equally likely to happen. Each box represents one way the parents' alleles can combine to form an offspring's genotype. Because there are four boxes in the Punnett square, there are four possible outcomes. An event is a set of one or more outcomes. The probability of an event is a measure of how likely the event is to happen. This probability is a number between 0 and 1, and it can be written as a fraction: probability of an event = number of ways the event can happen / number of equally likely outcomes You can use a Punnett square to calculate the probability that a cross will produce certain offspring. For example, the Punnett square below has two boxes with the genotype Ff. It has one box with the genotype FF and one box with the genotype ff. This means there are two ways the parents' alleles can combine to form Ff. There is one way they can combine to form FF and one way they can combine to form ff. | F | f F | FF | Ff f | Ff | ff Consider an event in which this cross produces an offspring with the genotype ff. The probability of this event is given by the following fraction: number of ways the event can happen / number of equally likely outcomes = number of boxes with the genotype ff / total number of boxes = 1 / 4

Compare the motion of three motorboats. Which motorboat was moving at the highest speed?

closed choice

grade3

natural science

physics

Force and motion

Compare the speeds of moving objects

An object's speed tells you how fast the object is moving. Speed depends on both distance and time. Distance tells you how far the object has moved. One unit used to measure distance is the mile. Time tells you how long the object has spent moving. One unit used to measure time is the hour. Think about objects moving for the same amount of time. The object that is moving the fastest will go the farthest distance in that time. It is moving at the highest speed.

Look at the distance each motorboat moved and the time it took to move that distance. The direction each motorboat moved does not affect its speed. Notice that each motorboat moved for 5 hours. The motorboat that moved 210 miles moved the farthest distance in that time. So, that motorboat must have moved at the highest speed.

Which text uses the word factoid in its traditional sense?

closed choice

grade9

language science

writing-strategies

Word usage and nuance

Explore words with new or contested usages

Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.

The second text uses factoid in its traditional sense: something made up presented as a true fact. As a geneticist, Kelly dislikes many popular sci-fi movies because they often present audiences with factoids that misrepresent her field. The first text uses factoid in its nontraditional sense: a trivial but true fact. As a geneticist, Kelly enjoys watching science documentaries and sharing various factoids she's learned with her colleagues. Most style guides recommend to use the traditional sense of the word factoid because it is considered more standard.

Does this passage describe the weather or the climate?

Figure: Washington, D.C.. Washington, D.C., is located on the East Coast of the United States. Last winter, on January 13, the city received over six inches of snow. Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.

closed choice

grade4

natural science

earth-science

Weather and climate

Weather and climate around the world

The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.

Read the passage carefully. Washington, D.C., is located on the East Coast of the United States. Last winter, on January 13, the city received over six inches of snow. The underlined part of the passage tells you about the amount of snow that fell on Washington, D.C., on January 13. This passage describes the atmosphere at a certain place and time. So, this passage describes the weather.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different shapes.

closed choice

grade7

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is smaller when there is a greater distance between the magnets.

Distance affects the magnitude of the magnetic force. When there is a greater distance between magnets, the magnitude of the magnetic force between them is smaller. There is a greater distance between the magnets in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is smaller in Pair 1 than in Pair 2.

Is there a surplus or a shortage of plane tickets?

There are 160 seats on a flight from New York to Chicago. Tickets for the flight cost $340. At that price, 230 people want to buy a ticket.

closed choice

grade5

social science

economics

Supply and demand

Identify shortage and surplus

There is a surplus if there is too much for sale at a given price. There is a shortage if there is not enough for sale at a given price. Surpluses and shortages usually happen when people who are selling goods or services charge too much or too little. When the price is too high, consumers will not want to buy much of the good or service. The quantity demanded will be less than the quantity supplied. So, there will be a surplus. When the price is too low, too many consumers will want to buy the good or service. The quantity demanded will be more than the quantity supplied. So, there will be a shortage.

At the current price, there are not enough tickets for sale. There are 160 tickets for sale, but 230 people want to buy one. So, there is a shortage of tickets.

What is the capital of Wyoming?

closed choice

grade3

social science

geography

State capitals

Identify the 50 state capitals

Cheyenne is the capital of Wyoming.

Which logical fallacy is used in the text? How could Mia have anything insightful to say about foreign affairs? She grew up on a farm.

closed choice

grade9

language science

writing-strategies

Developing and supporting arguments

Classify logical fallacies

A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions. A logical fallacy may present irrelevant information: Fallacy | Description ad hominem | an attack against the person making the argument, rather than the argument itself appeal to nature | an argument that assumes the natural choice is always the best choice bandwagon fallacy | an argument that assumes the popular choice is always the best choice circular reasoning | an argument that supports a claim with the claim itself guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something A logical fallacy may misrepresent the issues at hand: Fallacy | Description false causation | the assumption that because two things happened together, one caused the other false dichotomy | an argument that presents only two choices when more options exist hasty generalization | a broad claim based on too few observations slippery slope fallacy | the false assumption that a small first step will necessarily lead to extreme consequences straw man | a misrepresentation of an opponent's position that makes it easier to argue against

The text argues that Mia cannot be insightful about foreign affairs because she grew up on a farm. This is a personal attack that isn't relevant to whether she knows about foreign affairs. This illustrates a type of logical fallacy known as ad hominem.

Complete the sentence. The word "antebellum" means ().

The time period in United States history between 1820 and 1861 is often called the antebellum period. During the antebellum period, the North and South became more divided. In the following questions, you learn more about the changes that happened during the antebellum period. The following table shows other words that use the Latin root words ante and bellum. Look at the table. Then complete the text below.

closed choice

grade8

social science

us-history

The Antebellum period

Causes of the Civil War: Missouri Compromise to Bleeding Kansas

Look at the underlined parts of the table. All the words that use the root "ante" mean to come before something else. So, the root ante means "before." All the words that use the root "bellum" mean to fight or cause war.So, the root bellum means "war." So, the word "antebellum" means "before the war." The antebellum period is named for the war that followed it: the Civil War.

What is the capital of Minnesota?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Midwest

Saint Paul is the capital of Minnesota.

Which animal is also adapted to be camouflaged in a sandy desert?

s live in the deserts of southern Africa. The is adapted to be camouflaged in a sandy desert. Figure: Namaqua chameleon.

closed choice

grade5

natural science

biology

Adaptations

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Look at the picture of the Namaqua chameleon. The Namaqua chameleon has sand-colored scales covering its body. It is adapted to be camouflaged in a sandy desert. The word camouflage means to blend in. Now look at each animal. Figure out which animal has a similar adaptation. The bearded dragon has a sand-colored body. It is adapted to be camouflaged in a sandy desert. The merveille-du-jour moth has a green, black, and gray body. It is not adapted to be camouflaged in a sandy desert.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade8

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

The particles in both samples have the same average speed, but each particle in sample A has more mass than each particle in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

What is the capital of New Jersey?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Northeast

Trenton is the capital of New Jersey.

Which closing is correct for a letter?

closed choice

grade2

language science

capitalization

Capitalization

Greetings and closings of letters

A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory

The second closing is correct: Its first word is capitalized, and it ends with a comma.

Complete the statement. Chloroform is ().

Chloroform was once used for pain relief. It is no longer used because it can be dangerous to humans. The chemical formula for chloroform is CHCl3.

closed choice

grade5

natural science

chemistry

Atoms and molecules

Classify elementary substances and compounds using chemical formulas

Every substance around you is made of one or more chemical elements, or types of atoms. Substances that are made of only one chemical element are elementary substances. Substances that are made of two or more chemical elements bonded together are compounds. Every chemical element is represented by its own symbol. For some elements, the symbol is one capital letter. For other elements, the symbol is one capital letter and one lowercase letter. For example, the symbol for the element fluorine is F, and the symbol for the element beryllium is Be. The symbol for each element in a substance is shown in the substance's chemical formula. An elementary substance is represented by a chemical formula that contains only one symbol. The symbol may be followed by a subscript. A subscript is text that is smaller and placed lower than the normal line of text. A subscript is included when the atoms in the elementary substance are bonded to form molecules. The subscript tells you the number of atoms in each molecule. For example, the chemical formula for the elementary substance oxygen is O2. The formula has a subscript of 2. This subscript tells you that there are two atoms in the molecule represented by this chemical formula. The chemical element represented by the symbol O is also called oxygen. So, the formula O2 tells you that each molecule of O2 contains two oxygen atoms. A compound is represented by a chemical formula that contains multiple symbols. For example, in the compound beryllium fluoride, there is one beryllium atom for every two fluorine atoms. This combination is shown in the compound's chemical formula, BeF2. In the formula, the symbol Be represents one beryllium atom. The symbol F followed by the subscript 2 represents two fluorine atoms.

You can tell whether chloroform is an elementary substance or a compound by counting the number of symbols in its chemical formula. A symbol contains either one capital letter or a capital letter followed by one or two lowercase letters. The chemical formula for chloroform is CHCl3. This formula contains three symbols: C for carbon, H for hydrogen, and Cl for chlorine. So, the formula tells you that chloroform is made of three chemical elements bonded together. Substances made of two or more chemical elements bonded together are compounds. So, chloroform is a compound.

What can Francesca and Desmond trade to each get what they want?

Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another. Francesca and Desmond open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Francesca wanted broccoli in her lunch and Desmond was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

closed choice

grade6

social science

economics

Basic economic principles

Trade and specialization

Francesca wanted broccoli in her lunch and Desmond was hoping for tomatoes. Look at the labeled part of the images. Francesca has tomatoes. Desmond has broccoli. They can trade tomatoes for broccoli to both be happier. Trading other things would not help either person get more items they want.

Which animal's skin is better adapted as a warning sign to ward off predators?

Sharpnose-puffers are poisonous animals with brightly colored skin. The bright color serves as a warning sign that the animal is poisonous. The 's skin is adapted to ward off predators. Figure: sharpnose-puffer.

closed choice

grade4

natural science

biology

Adaptations

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Look at the picture of the sharpnose-puffer. The sharpnose-puffer has a poisonous body with brightly colored skin. Its skin is adapted to ward off predators. The bright colors serve as a warning sign that the sharpnose-puffer is poisonous. Now look at each animal. Figure out which animal has a similar adaptation. The opalescent nudibranch has stinging cells in its brightly colored skin. Its skin is adapted to ward off predators. The fantastic leaf-tailed gecko has reddish-brown skin. Its skin is not adapted to be a warning sign that wards off predators.

Compare the motion of two trains. Which train was moving at a higher speed?

closed choice

grade2

natural science

physics

Force and motion

Compare the speeds of moving objects

An object's speed tells you how fast the object is moving. Speed depends on both distance and time. Distance tells you how far the object has moved. One unit used to measure distance is the kilometer. Time tells you how long the object has spent moving. One unit used to measure time is the hour. Think about two objects moving for the same amount of time. The object that is moving faster will go a farther distance in that time. It is moving at a higher speed.

Look at the distance each train moved and the time it took to move that distance. One train moved 635 kilometers in 5 hours. The other train moved 605 kilometers in 5 hours. Notice that each train spent the same amount of time moving. The train that moved 635 kilometers moved a farther distance in that time. So, that train must have moved at a higher speed.

Does this passage describe the weather or the climate?

Figure: baseball game. The baseball players worried that the championship game might be rained out. Spring often brings low pressure systems with clouds and rain to the area near the stadium. Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.

closed choice

grade6

natural science

earth-science

Weather and climate

Weather and climate around the world

The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.

Read the passage carefully. The baseball players worried that the championship game might be rained out. Spring often brings low pressure systems with clouds and rain to the area near the stadium. The underlined part of the passage tells you about the usual pattern of barometric pressure near the stadium. This passage does not describe what the weather is like on a particular day. So, this passage describes the climate.

What is the capital of West Virginia?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Southeast

Charleston is the capital of West Virginia.

Which of these continents does the equator intersect?

closed choice

grade4

social science

geography

Maps

Use lines of latitude and longitude

Lines of latitude and lines of longitude are imaginary lines drawn on some globes and maps. They can help you find places on globes and maps. Lines of latitude show how far north or south a place is. We use units called degrees to describe how far a place is from the equator. The equator is the line located at 0° latitude. We start counting degrees from there. Lines north of the equator are labeled N for north. Lines south of the equator are labeled S for south. Lines of latitude are also called parallels because each line is parallel to the equator. Lines of longitude are also called meridians. They show how far east or west a place is. We use degrees to help describe how far a place is from the prime meridian. The prime meridian is the line located at 0° longitude. Lines west of the prime meridian are labeled W. Lines east of the prime meridian are labeled E. Meridians meet at the north and south poles. The equator goes all the way around the earth, but the prime meridian is different. It only goes from the North Pole to the South Pole on one side of the earth. On the opposite side of the globe is another special meridian. It is labeled both 180°E and 180°W. Together, lines of latitude and lines of longitude form a grid. You can use this grid to find the exact location of a place.

The equator is the line at 0° latitude. It intersects Africa. It does not intersect Europe or Antarctica.

Which of the following could Ernesto's test show?

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below. Ernesto was a landscape architect who was hired to design a new city park. The city council wanted the park to have space for outdoor concerts and to have at least 20% of the park shaded by trees. Ernesto thought the concert area should be at least 150 meters from the road so traffic noise didn't interrupt the music. He developed three possible designs for the park with the concert area in a different location in each design. Then, he tested each design by measuring the distance between the road and the concert area. Figure: studying an architect's design.

closed choice

grade8

natural science

science-and-engineering-practices

Engineering practices

Evaluate tests of engineering-design solutions

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. How can you determine what a test can show? You need to figure out what was tested and what was measured. Imagine an engineer needs to design a bridge for a windy location. She wants to make sure the bridge will not move too much in high wind. So, she builds a smaller prototype, or model, of a bridge. Then, she exposes the prototype to high winds and measures how much the bridge moves. First, identify what was tested. A test can examine one design, or it may compare multiple prototypes to each other. In the test described above, the engineer tested a prototype of a bridge in high wind. Then, identify what the test measured. One of the criteria for the bridge was that it not move too much in high winds. The test measured how much the prototype bridge moved. Tests can show how well one or more designs meet the criteria. The test described above can show whether the bridge would move too much in high winds.

Which type of force from the man's hand opens the car door?

A man gets into his car. His hand applies a force to the car door, and the door opens.

closed choice

grade3

natural science

physics

Force and motion

Identify pushes and pulls

A force is a push or a pull that one object applies to a second object. The direction of a push is away from the object that is pushing. The direction of a pull is toward the object that is pulling.

The man's hand applies a force to the car door. This force causes the door to open. The direction of this force is toward the man's hand. This force is a pull.

Select the one substance that is not a mineral.

closed choice

grade4

natural science

earth-science

Rocks and minerals

Identify minerals using properties

Minerals are the building blocks of rocks. A rock can be made of one or more minerals. Minerals and rocks have the following properties: Property | Mineral | Rock It is a solid. | Yes | Yes It is formed in nature. | Yes | Yes It is not made by organisms. | Yes | Yes It is a pure substance. | Yes | No It has a fixed crystal structure. | Yes | No You can use these properties to tell whether a substance is a mineral, a rock, or neither. Look closely at the last three properties: Minerals and rocks are not made by organisms. Organisms make their own body parts. For example, snails and clams make their shells. Because they are made by organisms, body parts cannot be minerals or rocks. Humans are organisms too. So, substances that humans make by hand or in factories are not minerals or rocks. A mineral is a pure substance, but a rock is not. A pure substance is made of only one type of matter. Minerals are pure substances, but rocks are not. Instead, all rocks are mixtures. A mineral has a fixed crystal structure, but a rock does not. The crystal structure of a substance tells you how the atoms or molecules in the substance are arranged. Different types of minerals have different crystal structures, but all minerals have a fixed crystal structure. This means that the atoms and molecules in different pieces of the same type of mineral are always arranged the same way. However, rocks do not have a fixed crystal structure. So, the arrangement of atoms or molecules in different pieces of the same type of rock may be different!

Compare the properties of each substance to the properties of minerals. Select the substance whose properties do not match those of minerals. Native gold is a mineral. Potassium feldspar is a mineral. A shark's tooth is not a pure substance. But all minerals are pure substances. So, a shark's tooth is not a mineral.

In this experiment, which were part of an experimental group?

The passage below describes an experiment. Layla was using steel to make rusted sculptures. After building each sculpture, she caused it to rust by placing it in salt water for eight hours. Layla wondered if steel would rust faster if she added vinegar to the salt water. Layla cut ten squares of steel sheet metal. She put five of the squares into a tub filled with salt water. She put the other five squares into a tub filled with salt water mixed with vinegar. Once an hour for eight hours, Layla counted how many steel squares in each group had rust on them. Figure: a sculpture made from rusted steel.

closed choice

grade7

natural science

science-and-engineering-practices

Designing experiments

Identify control and experimental groups

Experiments have variables, or parts that change. You can design an experiment to investigate whether changing a variable between different groups has a specific outcome. For example, imagine you want to find out whether adding fertilizer to soil affects the height of pea plants. You could investigate this question with the following experiment: You grow one group of pea plants in soil with fertilizer and measure the height of the plants. This group shows you what happens when fertilizer is added to soil. Since fertilizer is the variable whose effect you are investigating, this group is an experimental group. You grow another group of pea plants in soil without fertilizer and measure the height of the plants. Since this group shows you what happens when fertilizer is not added to the soil, it is a control group. By comparing the results from the experimental group to the results from the control group, you can conclude whether adding fertilizer to the soil affects pea plant height.

In this experiment, Layla investigated whether adding vinegar to salt water affects how quickly steel squares rust. So, the steel squares soaked in salt water and vinegar were part of an experimental group. The steel squares soaked in salt water did not get vinegar. So, they were not part of an experimental group.

Which of the following statements describess living in an independent city-state?

Athens was one of the most powerful independent city-states in ancient Greece. Look at the definitions below. Then answer the question.

closed choice

grade6

social science

world-history

Greece

Classical Athens: geography and society

Look at the definitions. Putting the definitions together, an independent city-state is a self-ruling city with its own government. So, a city-state rules itself and is not part of a larger country. The ancient Greeks called a city-state a polis, which was the ancient Greek word for city. Today, the root word "polis" is in the name of many cities, such as Minneapolis in Minnesota or Annapolis in Maryland.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.

closed choice

grade3

natural science

physics

Magnets

Compare strengths of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the strength of a magnetic force between two magnets by changing the distance between them. The magnetic force is weaker when the magnets are farther apart.

Distance affects the strength of the magnetic force. When magnets are farther apart, the magnetic force between them is weaker. The magnets in Pair 2 are farther apart than the magnets in Pair 1. So, the magnetic force is weaker in Pair 2 than in Pair 1.

Based on this information, what is this fruit fly's genotype for the body color gene?

In a group of fruit flies, some individuals have a gray body and others have a black body. In this group, the gene for the body color trait has two alleles. The allele B is for a gray body, and the allele b is for a black body. A certain fruit fly from this group has a gray body. This fly has two alleles for a gray body.

closed choice

grade6

natural science

biology

Genes to traits

Genetics vocabulary: genotype and phenotype

All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.

An organism's genotype for a gene is its combination of alleles for that gene. The fruit fly has two alleles for a gray body (B). So, the fly's genotype for the body color gene is BB.

What is the capital of Kansas?

closed choice

grade5

social science

geography

State capitals

Identify state capitals of the Midwest

Topeka is the capital of Kansas.

How long is a basketball court?

Select the better estimate.

closed choice

grade2

natural science

units-and-measurement

Units and measurement

Choose customary units of distance

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Imagine being told that a pencil is 8 long. You might be thinking, 8 what? Is the pencil 8 inches long? 8 feet? 8 miles? The number 8 on its own does not give you much information about the length of the pencil. That is because the units are missing. Now look at the drawing of the pencil and the ruler. The ruler shows that the units are inches. So, the length of the pencil is 8 inches. There are 12 inches in 1 foot. So, 1 inch is much shorter than 1 foot. There are 3 feet in 1 yard. So, 1 foot is shorter than 1 yard.

The better estimate for the length of a basketball court is 30 yards. 30 feet is too short.

Which of the following was an independent variable in this experiment?

The passage below describes an experiment. Read the passage and think about the variables that are described. Many types of bacteria cannot survive on objects made of copper. Dr. Duncan was considering using beds with copper bed rails instead of beds with plastic rails at the hospital where she worked. She wanted to know if copper bed rails would reduce the number of patients who got new infections. To test this, Dr. Duncan had beds with copper rails placed in half of the hospital rooms. Over the next six months, 430 patients were admitted to the hospital: 215 patients were put in rooms with copper bed rails and 215 patients were put in rooms with plastic bed rails. Dr. Duncan counted the number of patients in each type of room who got new infections while they were in the hospital. Hint: An independent variable is a variable whose effect you are investigating. A dependent variable is a variable that you measure. Figure: a hospital bed with plastic bed rails.

closed choice

grade6

natural science

science-and-engineering-practices

Designing experiments

Identify independent and dependent variables

Experiments have variables, or parts that change. You can design an experiment to find out how one variable affects another variable. For example, imagine that you want to find out if fertilizer affects the number of tomatoes a tomato plant grows. To answer this question, you decide to set up two equal groups of tomato plants. Then, you add fertilizer to the soil of the plants in one group but not in the other group. Later, you measure the effect of the fertilizer by counting the number of tomatoes on each plant. In this experiment, the amount of fertilizer added to the soil and the number of tomatoes were both variables. The amount of fertilizer added to the soil was an independent variable because it was the variable whose effect you were investigating. This type of variable is called independent because its value does not depend on what happens after the experiment begins. Instead, you decided to give fertilizer to some plants and not to others. The number of tomatoes was a dependent variable because it was the variable you were measuring. This type of variable is called dependent because its value can depend on what happens in the experiment.

Which correctly shows the title of a movie?

closed choice

grade9

language science

punctuation

Formatting

Formatting titles

The title of a book, movie, play, TV show, magazine, or newspaper should be in italics. If you write it by hand, it can be underlined instead. A Midsummer Night's Dream The title of a poem, song, article, or short story should be in quotation marks. "You Are My Sunshine"

A movie should be in italics. The correct title is **Now You See Me**.

Which material is this bowl made of?

closed choice

grade2

natural science

physics

Materials

Identify materials in objects

A material is a type of matter. Wood, glass, metal, and plastic are common materials.

Look at the picture of the bowl. The bowl is made of glass. Glass is a clear, breakable material. Some clear bowls are made of glass, and others are made of plastic. Plastic does not break as easily as glass does.

Complete the sentence. The Fourth Amendment says that the government needs to have a good reason before it can () a person.

closed choice

grade4

social science

civics

Government

The Bill of Rights

The Fourth Amendment says that the government needs to have a good reason before it can search a person or his or her property. The Fourth Amendment says that "unreasonable searches" are not allowed. It is not always clear what makes a search "unreasonable." But a search for no reason is definitely unreasonable! Police officers and other government employees search people every day. There are many good reasons the government might have to search someone. For example, the person might be acting in a suspicious or strange way. Or a police officer might see something against the law before the search. It is often hard to know if the government has a good enough reason to do a search. Often a judge will have to decide. The full text of the Fourth Amendment is below. How can a police officer or other member of the government get the right to search someone? The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Which statement describes the asteroid's motion?

An asteroid is flying directly toward Mars at a steady speed.

closed choice

grade8

natural science

physics

Velocity, acceleration, and forces

Identify whether objects are accelerating

An object's velocity describes its speed and its direction. An object has a constant velocity when neither its speed nor its direction is changing. So, an object has a constant velocity when the object is: moving in a straight line at a constant speed, or remaining motionless. If an object does not have a constant velocity, the object is accelerating. An object is accelerating when either its speed or its direction is changing. So, an object is accelerating when the object is: speeding up, slowing down, or changing direction.

The asteroid is moving in a straight line at a constant speed. So, the asteroid has a constant velocity.

Which figure of speech is used in this text? You've reached Andy Conway's voice mail. Please leave a detailed message at the beep, and I will return your call at my earliest convenience.

closed choice

grade6

language science

figurative-language

Literary devices

Classify figures of speech

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Alliteration is the repetition of sounds at the beginning of nearby words. What a lucky little lady you are! An allusion is a brief reference to something or someone well known, often from history or literature. "I'd better get home before I turn into a pumpkin!" Lila remarked. An idiom is an expression that cannot be understood literally. Its meaning must be learned. The assignment was a piece of cake. A simile uses like or as to compare two things that are not actually alike. The cat's fur was as dark as the night. A metaphor compares two things that are not actually alike without using like or as. The snow formed a blanket over the town. Onomatopoeia involves using a word that expresses a sound. The scrambled eggs hit the floor with a splat. Personification is giving human characteristics to nonhuman things. The trees danced in the wind. A pun involves using a word or phrase in a humorous way that suggests more than one meaning. A great new broom is sweeping the nation. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.

The text uses onomatopoeia, a word that expresses a sound. Beep represents the sound that tells the caller to start recording a message.

Select the chemical formula for this molecule.

closed choice

grade7

natural science

chemistry

Atoms and molecules

Identify chemical formulas for ball-and-stick models

Every substance around you is made up of atoms. Atoms can link together to form molecules. The links between atoms in a molecule are called chemical bonds. Different molecules are made up of different chemical elements, or types of atoms, bonded together. Scientists use both ball-and-stick models and chemical formulas to represent molecules. A ball-and-stick model of a molecule is shown below. The balls represent atoms. The sticks represent the chemical bonds between the atoms. Balls that are different colors represent atoms of different elements. The element that each color represents is shown in the legend. Every element has its own abbreviation, called its atomic symbol. Every chemical element is represented by its own symbol. For some elements, that symbol is one capital letter. For other elements, it is one capital letter followed by one lowercase letter. For example, the symbol for the element boron is B and the symbol for the element chlorine is Cl. The molecule shown above has one boron atom and three chlorine atoms. A chemical bond links each chlorine atom to the boron atom. The chemical formula for a substance contains the atomic symbol for each element in the substance. Many chemical formulas also contain subscripts. A subscript is small text placed lower than the normal line of text. Each subscript in a chemical formula is placed after the symbol for an element and tells you how many atoms of that element that symbol represents. If there is no subscript after a symbol, that symbol represents one atom. So, the chemical formula for a substance tells you which elements make up that substance. It also tells you the ratio of the atoms of those elements in the substance. For example, the chemical formula below tells you that there are three chlorine atoms for every one boron atom in the substance. This chemical formula represents the same substance as the ball-and-stick model shown above.

C is the symbol for carbon. According to the legend, carbon atoms are shown in dark gray. H is the symbol for hydrogen. According to the legend, hydrogen atoms are shown in light gray. This ball-and-stick model shows a molecule with one carbon atom and four hydrogen atoms. The chemical formula will contain the symbols C and H. There is one carbon atom, so C will not have a subscript. There are four hydrogen atoms, so H will have a subscript of 4. The correct formula is CH4. The diagram below shows how each part of the chemical formula matches with each part of the model above.

What is the mass of an elephant?

Select the better estimate.

closed choice

grade5

natural science

units-and-measurement

Units and measurement

Choose metric units of mass

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Mass is a measurement of how much matter something contains. There are many different units of mass. When you are using metric units, mass may be written with units of grams or kilograms. There are 1,000 grams in 1 kilogram. So, 1 gram is much less than 1 kilogram. A paper clip has a mass of about 1 gram, while a textbook has a mass of about 1 kilogram.

The better estimate for the mass of an elephant is 5,220 kilograms. 5,220 grams is too light.

Which word is not like the others?

closed choice

grade2

language science

vocabulary

Categories

Which word is not like the others?

Some words are alike. They go together in a group. Red, blue, and green go together. They are colors. Mom, dad, grandma, and grandpa go together. They are people in a family.

Cent, penny, and dollar go together. They are money. Buy is not money, so it is not like the other words.

Select the one true statement.

closed choice

grade7

natural science

biology

Cells

Compare cells and cell parts

Based on this information, what is this plant's phenotype for the flower position trait?

This passage describes the flower position trait in pea plants: In a group of pea plants, some individuals have axial flowers and others have terminal flowers. In this group, the gene for the flower position trait has two alleles. The allele for terminal flowers (f) is recessive to the allele for axial flowers (F). A certain pea plant from this group has the homozygous genotype ff for the flower position gene.

closed choice

grade8

natural science

biology

Genes to traits

Genetics vocabulary: dominant and recessive

All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait. Some traits, like flower color in pea plants, are controlled by a single gene. Most plants and animals have a genotype made up of two alleles for these traits. These two alleles determine whether an organism is homozygous or heterozygous for the gene. An organism with two identical alleles for a gene is homozygous for that gene. A pea plant with the genotype FF or ff is homozygous for the flower color gene. An organism with two different alleles for a gene is heterozygous for that gene. A pea plant with the genotype Ff is heterozygous for the flower color gene. The types of alleles in an organism's genotype determine the organism's phenotype. Some alleles have types called dominant and recessive. These two types can cause different versions of a trait to appear as the organism's phenotype. A dominant allele causes its version of the trait to appear even when the organism also has a recessive allele for the gene. In pea plants, the F allele, which causes purple flowers, is dominant over the f allele. A pea plant with at least one F allele will have the F allele's version of the flower color trait. So, a plant with the genotype FF or Ff will have purple flowers. A recessive allele causes its version of the trait to appear only when the organism does not have any dominant alleles for the gene. In pea plants, the f allele, which causes white flowers, is recessive to the F allele. A pea plant with only f alleles will have the f allele's version of the flower color trait. So, a plant with the genotype ff will have white flowers.

The pea plant's genotype for the flower position gene is ff. The pea plant's genotype of ff has only f alleles. The f allele is for terminal flowers. So, the pea plant's phenotype for the flower position trait must be terminal flowers. To check this answer, consider whether the pea plant's alleles are dominant or recessive. The allele for terminal flowers (f) is recessive to the allele for axial flowers (F). This means F is a dominant allele, and f is a recessive allele. The pea plant's genotype of ff has only recessive alleles. An organism with only recessive alleles for a gene will have the recessive allele's version of the trait. So, the pea plant's phenotype for the flower position trait must be terminal flowers.

Which ocean is highlighted?

closed choice

grade8

social science

geography

Physical Geography

Oceans and continents

Oceans are huge bodies of salt water. The world has five oceans. All of the oceans are connected, making one world ocean.

This is the Indian Ocean.

What is the capital of Utah?

closed choice

grade3

social science

geography

State capitals

Identify the 50 state capitals

Salt Lake City is the capital of Utah.

What do these two changes have in common? bending a paper clip mixing sand and water

closed choice

grade3

natural science

chemistry

Physical and chemical change

Compare physical and chemical changes

Chemical changes and physical changes are two common ways matter can change. In a chemical change, the type of matter changes. The types of matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. When paper gets hot enough, it re­acts with oxygen in the air and burns. The paper and oxygen change into ash and smoke. In a physical change, the type of matter stays the same. The types of matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, ice melting is a physical change that can be caused by heating. Ice and liquid water are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.

Step 1: Think about each change. Bending a paper clip is a physical change. After you bend it, the paper clip has a different shape. But it is still made of the same type of matter. Mixing sand and water is a physical change. Adding water makes the sand wet. But both the sand and water are still made of the same type of matter as before. Step 2: Look at each answer choice. Both are only physical changes. Both changes are physical changes. No new matter is created. Both are chemical changes. Both changes are physical changes. They are not chemical changes. Both are caused by heating. Neither change is caused by heating. Both are caused by cooling. Neither change is caused by cooling.

Would you find the word tangle on a dictionary page with the following guide words? throttle - truth

yes or no

grade6

language science

reference-skills

Reference skills

Use guide words

Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.

Put the words in alphabetical order. Since tangle is not between the guide words throttle - truth, it would not be found on that page.

Which word is not like the others?

closed choice

grade2

language science

vocabulary

Categories

Which word is not like the others?

Some words are alike. They go together in a group. Red, blue, and green go together. They are colors. Mom, dad, grandma, and grandpa go together. They are people in a family.

Dollar, cent, and penny go together. They are money. Sell is not money, so it is not like the other words.

Is this a sentence fragment? By the time the Guerra Bianca, or White War, ended in 1917, Italian and Austro-Hungarian soldiers fighting for three years in extreme conditions at altitudes of up to twelve thousand feet.

yes or no

grade12

language science

writing-strategies

Sentences, fragments, and run-ons

Identify sentence fragments

A sentence is a group of words that expresses a complete thought. The band I'm in has been rehearsing daily because we have a concert in two weeks. A sentence fragment is a group of words that does not express a complete thought. Rehearsing daily because we have a concert in two weeks. This fragment is missing a subject. It doesn't tell who is rehearsing. The band I'm in. This fragment is missing a verb. It doesn't tell what the band I'm in is doing. Because we have a concert in two weeks. This fragment is missing an independent clause. It doesn't tell what happened because of the concert.

This is a sentence fragment. It does not express a complete thought. By the time the Guerra Bianca, or White War, ended in 1917, Italian and Austro-Hungarian soldiers fighting for three years in extreme conditions at altitudes of up to twelve thousand feet. Here is one way to fix the sentence fragment: By the time the Guerra Bianca, or White War, ended in 1917, Italian and Austro-Hungarian soldiers had been fighting for three years in extreme conditions at altitudes of up to twelve thousand feet.

What do these two changes have in common? ice melting in a glass molding clay into the shape of a pot

closed choice

grade3

natural science

chemistry

Physical and chemical change

Compare physical and chemical changes

Chemical changes and physical changes are two common ways matter can change. In a chemical change, the type of matter changes. The types of matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. When paper gets hot enough, it re­acts with oxygen in the air and burns. The paper and oxygen change into ash and smoke. In a physical change, the type of matter stays the same. The types of matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, ice melting is a physical change that can be caused by heating. Ice and liquid water are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.

Step 1: Think about each change. Ice melting in a glass is a change of state. So, it is a physical change. The solid ice becomes liquid, but it is still made of water. A different type of matter is not made. Molding clay into the shape of a pot is a physical change. The clay gets a different shape. But it is made of the same type of matter. Step 2: Look at each answer choice. Both are only physical changes. Both changes are physical changes. No new matter is created. Both are chemical changes. Both changes are physical changes. They are not chemical changes. Both are caused by heating. Ice melting is caused by heating. But molding clay is not. Both are caused by cooling. Neither change is caused by cooling.

Which of these states is farthest south?

closed choice

grade4

social science

geography

Maps

Read a map: cardinal directions

Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west. A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction. The north arrow points to the North Pole. On most maps, north is at the top of the map.

To find the answer, look at the compass rose. Look at which way the south arrow is pointing. Indiana is farthest south.

Which object has the most thermal energy?

The objects are identical except for their temperatures.

closed choice

grade4

natural science

physics

Heat and thermal energy

How is temperature related to thermal energy?

All solids, liquids, and gases are made of matter. Matter is made up of tiny particles that are always moving. The energy from the motion of these particles is called thermal energy. Temperature measures how hot or cold matter is. If the particles in matter move faster, the temperature goes up. The matter now has both more thermal energy and a higher temperature.

All three glasses of water have the same mass but different temperatures. Since the 85°F glass of water is the hottest, it has the most thermal energy.

What is the capital of New Jersey?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Northeast

Trenton is the capital of New Jersey.

What is the temperature of a pot of boiling soup?

Select the better estimate.

closed choice

grade7

natural science

units-and-measurement

Units and measurement

Estimate temperatures

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Temperature can be written with units of degrees Fahrenheit (°F) or Celsius (°C). Use the list below to compare the two units. 212°F | Water boils | 100°C 98.6°F | Body temperature | 37°C 68°F | Room temperature | 20°C 32°F | Water freezes | 0°C

The better estimate for the temperature of a pot of boiling soup is 215°F. 215°C is too hot.

What is the capital of Massachusetts?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Northeast

Boston is the capital of Massachusetts.

Which text uses the word terribly in its traditional sense?

closed choice

grade12

language science

writing-strategies

Word usage and nuance

Explore words with new or contested usages

Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.

The first text uses terribly in its traditional sense: in a terrible manner. Arianna decided to make escargots using the small snails from her garden, but she prepared them terribly. Since she'd forgotten to add garlic, the taste was disappointing. The second text uses terribly in its nontraditional sense: extremely; very. Arianna made escargots using the small snails from her garden. She prepared them according to the recipe but found the chewy texture terribly disappointing. Most style guides recommend to use the traditional sense of the word terribly because it is considered more standard.

Complete the statement. Lithium chloride is ().

Lithium chloride can be used to create red fireworks. The chemical formula for lithium chloride is LiCl.

closed choice

grade8

natural science

chemistry

Atoms and molecules

Classify elementary substances and compounds using chemical formulas

There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you. A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds. Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element fluorine is F, and the atomic symbol for the chemical element beryllium is Be. The atomic symbol for each chemical element in a substance is shown in the substance's chemical formula. An elementary substance is represented by a chemical formula that contains only one atomic symbol. The atomic symbol in a chemical formula may be followed by a small number written lower than the symbol. This number is called a subscript. A subscript is included when the atoms in the elementary substance are bonded to form molecules. The subscript shows how many atoms are in each molecule. For example, the chemical formula for the elementary substance oxygen, O2, has a subscript of 2. This subscript shows that the atomic symbol O represents two atoms. The elementary substance O2 and the chemical element represented by the atomic symbol O are both named oxygen. So, the formula tells you that each molecule of O2 contains two oxygen atoms. A compound is represented by a chemical formula that contains multiple atomic symbols. The chemical elements in a compound are bonded together in a fixed ratio. This ratio is shown in a compound's chemical formula. For example, in the compound beryllium fluoride, there is one beryllium atom for every two fluorine atoms. So, the ratio of beryllium atoms to fluorine atoms is 1 to 2. This ratio is shown in the chemical formula for beryllium fluoride, BeF2. There is no subscript following the atomic symbol Be because that symbol represents one atom. The subscript 2 follows the atomic symbol F to show that the symbol represents two atoms.

You can tell whether lithium chloride is an elementary substance or a compound by counting the number of atomic symbols in its chemical formula. An atomic symbol consists of either one capital letter or a capital letter followed by one or two lowercase letters. The chemical formula for lithium chloride, LiCl, contains two atomic symbols: Li for lithium and Cl for chlorine. So, the formula tells you that lithium chloride is composed of two chemical elements bonded together. Since lithium chloride is composed of multiple chemical elements bonded together, lithium chloride is a compound.

Select the invertebrate.

Hint: Insects, spiders, and worms are invertebrates.

closed choice

grade5

natural science

biology

Classification

Identify vertebrates and invertebrates

Vertebrates and invertebrates are both groups of animals. A vertebrate has a backbone. The backbone is made of many bones in an animal's back. A vertebrate's backbone helps connect the different parts of its body. In the drawings below, each vertebrate's backbone is colored orange. An invertebrate does not have a backbone. In fact, invertebrates do not have any bones! Some invertebrates have an outer cover on their body called an exoskeleton. Other invertebrates have a soft body.

A whiptail lizard is a reptile. Like other reptiles, a whiptail lizard is a vertebrate. It has a backbone. A cockatoo is a bird. Like other birds, a cockatoo is a vertebrate. It has a backbone. A human is a mammal. Like other mammals, a human is a vertebrate. It has a backbone. A pipevine swallowtail butterfly is an insect. Like other insects, a pipevine swallowtail butterfly is an invertebrate. It does not have a backbone. It has an exoskeleton.

What is the volume of a large soup pot?

Select the better estimate.

closed choice

grade4

natural science

units-and-measurement

Units and measurement

Choose metric units of volume

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Volume is a measurement of how much space something takes up. There are many different units of volume. When you are using metric units, volume may be written in units of milliliters or liters. There are 1,000 milliliters in 1 liter. So, 1 milliliter is much less than 1 liter. A raindrop has a volume of about 20 milliliters, while a large soda bottle has a volume of 2 liters. The flask shown here measures volumes up to 500 milliliters.

The better estimate for the volume of a large soup pot is 6 liters. 6 milliliters is too little.

Which continent is highlighted?

closed choice

grade6

social science

geography

Physical Geography

Oceans and continents

A continent is one of the major land masses on the earth. Most people say there are seven continents.

This continent is Europe.

Which would stretch more?

closed choice

grade2

natural science

physics

Materials

Compare properties of materials

Every object is made of one or more materials. A material is a type of matter. Wood, glass, metal, and plastic are common materials. A material has different properties. A material's properties tell you how it looks, feels, tastes, or smells.

Stretchy is a property. A stretchy material gets longer when you pull on it. Look at each picture, one at a time. Imagine pulling on the material shown in each picture. Of the choices, the nylon swim shorts would stretch more. If you pull the leg opening on a pair of nylon swim shorts, it will get wider.

What is the expected ratio of offspring with curly fur to offspring with straight fur? Choose the most likely ratio.

In a group of cats, some individuals have straight fur and others have curly fur. In this group, the gene for the fur type trait has two alleles. The allele for straight fur (F) is dominant over the allele for curly fur (f). This Punnett square shows a cross between two cats.

closed choice

grade8

natural science

biology

Genes to traits

Use Punnett squares to calculate ratios of offspring types

Offspring phenotypes: dominant or recessive? How do you determine an organism's phenotype for a trait? Look at the combination of alleles in the organism's genotype for the gene that affects that trait. Some alleles have types called dominant and recessive. These two types can cause different versions of the trait to appear as the organism's phenotype. If an organism's genotype has at least one dominant allele for a gene, the organism's phenotype will be the dominant allele's version of the gene's trait. If an organism's genotype has only recessive alleles for a gene, the organism's phenotype will be the recessive allele's version of the gene's trait. A Punnett square shows what types of offspring a cross can produce. The expected ratio of offspring types compares how often the cross produces each type of offspring, on average. To write this ratio, count the number of boxes in the Punnett square representing each type. For example, consider the Punnett square below. | F | f F | FF | Ff f | Ff | ff There is 1 box with the genotype FF and 2 boxes with the genotype Ff. So, the expected ratio of offspring with the genotype FF to those with Ff is 1:2.

To determine how many boxes in the Punnett square represent offspring with curly fur or straight fur, consider whether each phenotype is the dominant or recessive allele's version of the fur type trait. The question tells you that the F allele, which is for straight fur, is dominant over the f allele, which is for curly fur. Curly fur is the recessive allele's version of the fur type trait. A cat with the recessive version of the fur type trait must have only recessive alleles for the fur type gene. So, offspring with curly fur must have the genotype ff. There are 2 boxes in the Punnett square with the genotype ff. These boxes are highlighted below. Straight fur is the dominant allele's version of the fur type trait. A cat with the dominant version of the fur type trait must have at least one dominant allele for the fur type gene. So, offspring with straight fur must have the genotype FF or Ff. There are 2 boxes in the Punnett square with the genotype FF or Ff. These boxes are highlighted below. So, the expected ratio of offspring with curly fur to offspring with straight fur is 2:2. This means that, on average, this cross will produce 2 offspring with curly fur for every 2 offspring with straight fur.

Which type of force from the bulldozer clears the path?

A bulldozer clears a path for a new road. The bulldozer applies a force to the loose dirt in front of the blade.

closed choice

grade3

natural science

physics

Force and motion

Identify pushes and pulls

A force is a push or a pull that one object applies to a second object. The direction of a push is away from the object that is pushing. The direction of a pull is toward the object that is pulling.

The bulldozer applies a force to the loose dirt and clears the path. The direction of this force is away from the bulldozer. This force is a push.

Which greeting is correct for a letter?

closed choice

grade3

language science

punctuation

Formatting

Greetings and closings of letters

A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory

The first greeting is correct: Its first word is capitalized, and it ends with a comma. Dr. McKnight is capitalized because it is a proper noun.

What do these two changes have in common? an old sandwich rotting in a trashcan baking cookies

closed choice

grade4

natural science

chemistry

Physical and chemical change

Compare physical and chemical changes

Chemical changes and physical changes are two common ways matter can change. In a chemical change, the type of matter changes. The types of matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. When paper gets hot enough, it re­acts with oxygen in the air and burns. The paper and oxygen change into ash and smoke. In a physical change, the type of matter stays the same. The types of matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, ice melting is a physical change that can be caused by heating. Ice and liquid water are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.

Step 1: Think about each change. A sandwich rotting is a chemical change. The matter in the sandwich breaks down and slowly turns into a different type of matter. Baking cookies is a chemical change. The type of matter in the cookie dough changes when it is baked. The cookie dough turns into cookies! Step 2: Look at each answer choice. Both are only physical changes. Both changes are chemical changes. They are not physical changes. Both are chemical changes. Both changes are chemical changes. The type of matter before and after each change is different. Both are caused by heating. Baking is caused by heating. But a sandwich rotting is not. Both are caused by cooling. Neither change is caused by cooling.

What is the source of the allusion in the sentence below? Ben says that he would not be the person he is today were it not for his childhood, which he describes as Dickensian.

closed choice

grade10

language science

figurative-language

Literary devices

Recall the source of an allusion

An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. "I'd better get home before I turn into a pumpkin!" Lila remarked. Here, Lila alludes to the fairy tale "Cinderella," in which Cinderella must leave the ball before the coach that brought her transforms into a pumpkin. The allusion shows that Lila must depart immediately.

The source of the allusion Dickensian is literature. The works of British author Charles Dickens often featured characters struggling to survive in settings such as debtors' prisons and orphanages. The allusion Dickensian means harsh or poverty-stricken.

Select the amphibian.

closed choice

grade5

natural science

biology

Classification

Identify mammals, birds, fish, reptiles, and amphibians

Amphibians have moist skin and begin their lives in water.

A red-headed poison frog is an amphibian. It has moist skin and begins its life in water. Poison dart frogs come in many bright colors. Their bright color warns other animals that these frogs are poisonous. A black howler is a mammal. It has hair and feeds its young milk. Howler monkeys have loud calls, or howls. Their calls can be heard over three miles away! A thresher shark is a fish. It lives underwater. It has fins, not limbs. A thresher shark has a long tail. It can use its tail to hit and stun prey. A salmon is a fish. It lives underwater. It has fins, not limbs. Unlike most other fish, salmon can live in both fresh water and salt water.

What do these two changes have in common? water evaporating from a lake dry ice sublimating and becoming a gas

closed choice

grade7

natural science

chemistry

Chemical reactions

Compare physical and chemical changes

Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.

Step 1: Think about each change. Water evaporating from a lake is a change of state. So, it is a physical change. The liquid changes into a gas, but a different type of matter is not formed. Dry ice is solid carbon dioxide. When dry ice gets warm, it changes state and becomes carbon dioxide gas. This change of state, from solid to gas, is called sublimation. Dry ice becoming a gas is a physical change. A change of state does not form a different type of matter. Step 2: Look at each answer choice. Both are only physical changes. Both changes are physical changes. No new matter is created. Both are chemical changes. Both changes are physical changes. They are not chemical changes. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.

Will these magnets attract or repel each other?

Two magnets are placed as shown. Hint: Magnets that attract pull together. Magnets that repel push apart.

closed choice

grade2

natural science

physics

Magnets

Identify magnets that attract or repel

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends. Every magnet has two poles, called north and south. Here are some examples of magnets. The north pole of each magnet is marked N, and the south pole is marked S. If different poles are closest to each other, the magnets attract. The magnets in the pair below attract. If the same poles are closest to each other, the magnets repel. The magnets in both pairs below repel.

Will these magnets attract or repel? To find out, look at which poles are closest to each other. The north pole of one magnet is closest to the south pole of the other magnet. Poles that are different attract. So, these magnets will attract each other.

What can Brennan and Ed trade to each get what they want?

Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another. Brennan and Ed open their lunch boxes in the school cafeteria. Neither Brennan nor Ed got everything that they wanted. The table below shows which items they each wanted: Look at the images of their lunches. Then answer the question below. Brennan's lunch Ed's lunch

closed choice

grade7

social science

economics

Basic economic principles

Trade and specialization

Look at the table and images. Brennan wants broccoli. Ed wants tomatoes. They can trade tomatoes for broccoli to both get what they want. Trading other things would not help both people get more items they want.

Last year, 50,000 people lived in the city of Riverside. But since then, 8,000 people have moved away. What probably happened to the overall supply of houses for sale in Riverside?

closed choice

grade5

social science

economics

Supply and demand

Understand overall supply and demand

Overall supply is the total amount of a good or service that producers make and sell. There are several things that can make overall supply go up or down. The table below shows how changes to these things might affect overall supply. | Resources | Number of producers or suppliers | Expected change in demand Supply goes up | when resources cost less or are easier to get | when there are more producers or suppliers | when demand is expected to go up Supply goes down | when resources cost more or are harder to get | when there are fewer producers or suppliers | when demand is expected to go down Producers are people or companies that make goods or provide services. Suppliers are people or companies that sell goods or services. New inventions or technologies can also help workers produce goods and services more quickly. As a result of these changes, the supply of a good or service will often go up.

The population of Riverside fell by 8,000 people. Many of the people who have left are probably trying to sell their houses. Since more people are trying to sell their houses, the number of suppliers of houses for sale in Riverside has gone up. So, the supply of houses for sale probably went up, too.

Which object has more thermal energy?

The objects are identical except for their temperatures.

closed choice

grade3

natural science

physics

Heat and thermal energy

How is temperature related to thermal energy?

All solids, liquids, and gases are made of matter. Matter is made up of tiny particles that are always moving. The energy from the motion of these particles is called thermal energy. Temperature measures how hot or cold matter is. If the particles in matter move faster, the temperature goes up. The matter now has both more thermal energy and a higher temperature.

The two glasses of grape juice have the same mass but different temperatures. Since the 20°C glass of grape juice is hotter than the 5°C glass of grape juice, it has more thermal energy.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different shapes.

closed choice

grade6

natural science

physics

Velocity, acceleration, and forces

Compare magnitudes of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.

Both magnet sizes and distance affect the magnitude of the magnetic force. The sizes of the magnets in Pair 1 are the same as in Pair 2. The distance between the magnets is also the same. So, the magnitude of the magnetic force is the same in both pairs.

What is the capital of West Virginia?

closed choice

grade5

social science

geography

State capitals

Identify state capitals of the Southeast

Charleston is the capital of West Virginia.

Select the organism in the same genus as the Japanese tree frog.

This organism is a Japanese tree frog. Its scientific name is Hyla japonica.

closed choice

grade5

natural science

biology

Scientific names

Use scientific names to classify organisms

Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.

A Japanese tree frog's scientific name is Hyla japonica. The first word of its scientific name is Hyla. Hyla cinerea is in the genus Hyla. The first word of its scientific name is Hyla. So, Hyla cinerea and Hyla japonica are in the same genus. Lonicera japonica and Hyla japonica are not in the same genus. These organisms are not in the same genus, but part of their scientific names is the same. Lonicera japonica and Hyla japonica have the same species name within their genus, japonica. But the first words of their scientific names are different. Lonicera japonica is in the genus Lonicera, and Hyla japonica is in the genus Hyla. Strix nebulosa is in the genus Strix. The first word of its scientific name is Strix. So, Strix nebulosa and Hyla japonica are not in the same genus.

Which logical fallacy is used in the text? The number of off-leash dogs I've seen in Silvergrove is completely unacceptable. Let's make our streets safe again by addressing this dog problem, before our city becomes a haven for criminals.

closed choice

grade7

language science

writing-strategies

Developing and supporting arguments

Classify logical fallacies

A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions. A logical fallacy may present irrelevant information: Fallacy | Description ad hominem | a personal attack meant to discredit one's opponent appeal to nature | an argument that assumes the natural choice is always the best choice bandwagon fallacy | an argument that assumes the popular choice is always the best choice circular reasoning | an argument that supports a claim with the claim itself guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something red herring | the use of a completely unrelated topic in support of a claim A logical fallacy may misrepresent the issues at hand: Fallacy | Description false causation | the assumption that because two things happened together, one caused the other false dichotomy | an argument that presents only two choices when more options exist hasty generalization | a very broad claim based on very little evidence straw man | a misrepresentation of an opponent's position that makes it easier to argue against

The text argues that off-leash dogs would somehow cause an increase in crime in Silvergrove. However, these two ideas aren't related. This illustrates a type of logical fallacy known as a red herring.

Which of the following could Joseph's test show?

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below. Joseph was installing solar panels on the roof of a client's house. The panels had to provide enough electricity to power the house year-round. Joseph needed to decide how many panels to install and which side of the roof to install them on. If he put the panels on the side that got the most sun, then he could use fewer panels, and the client would save money. Joseph installed sunlight sensors on both sides of the roof. Then, he measured the amount of sunlight the sensors on each side of the roof recorded over one sunny summer day. Figure: installing solar panels on a roof.

closed choice

grade7

natural science

science-and-engineering-practices

Engineering practices

Evaluate tests of engineering-design solutions

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. How can you determine what a test can show? You need to figure out what was tested and what was measured. Imagine an engineer needs to design a bridge for a windy location. She wants to make sure the bridge will not move too much in high wind. So, she builds a smaller prototype, or model, of a bridge. Then, she exposes the prototype to high winds and measures how much the bridge moves. First, identify what was tested. A test can examine one design, or it may compare multiple prototypes to each other. In the test described above, the engineer tested a prototype of a bridge in high wind. Then, identify what the test measured. One of the criteria for the bridge was that it not move too much in high winds. The test measured how much the prototype bridge moved. Tests can show how well one or more designs meet the criteria. The test described above can show whether the bridge would move too much in high winds.

Is Bertholletia excelsa made up of many cells?

This organism is Bertholletia excelsa. It is a member of the plant kingdom. Bertholletia excelsa is commonly called a Brazil nut tree. Brazil nut trees have a tall, thin trunk. Branches grow near the top of the tree. A Brazil nut tree can live for over 500 years!

yes or no

grade4

natural science

biology

Classification

Describe, classify, and compare kingdoms

In the past, scientists classified living organisms into two groups: plants and animals. Over the past 300 years, scientists have discovered many more types of organisms. Today, many scientists classify organisms into six broad groups, called kingdoms. Organisms in each kingdom have specific traits. The table below shows some traits used to describe each kingdom. | Bacteria | Archaea | Protists | Fungi | Animals | Plants How many cells do they have? | one | one | one or many | one or many | many | many Do their cells have a nucleus? | no | no | yes | yes | yes | yes Can their cells make food? | some species can | some species can | some species can | no | no | yes

Bertholletia excelsa is a plant. Plants are made up of many cells.

Complete the statement. Bromine is ().

The model below represents a molecule of bromine. Liquid bromine is made in chemical factories. It can be used to make couches and mattresses that are fire-resistant.

closed choice

grade7

natural science

chemistry

Atoms and molecules

Classify elementary substances and compounds using models

There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you. A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds. Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element boron is B, and the atomic symbol for the chemical element chlorine is Cl. Scientists use different types of models to represent substances whose atoms are bonded in different ways. One type of model is a ball-and-stick model. The ball-and-stick model below represents a molecule of the compound boron trichloride. In a ball-and-stick model, the balls represent atoms, and the sticks represent bonds. Notice that the balls in the model above are not all the same color. Each color represents a different chemical element. The legend shows the color and the atomic symbol for each chemical element in the substance.

Use the model to determine whether bromine is an elementary substance or a compound. Step 1: Interpret the model. In the ball-and-stick model shown above, both of the balls are the same color: . The legend shows that dark red represents the chemical element with the atomic symbol Br. So, the model shows you that a molecule of bromine is composed of one chemical element. Step 2: Determine whether the substance is an elementary substance or a compound. You know from Step 1 that bromine is composed of only one chemical element. So, bromine is an elementary substance.

Is there a sentence fragment? Spring and fall—the best times to enjoy the lake and avoid the crowds of summer. No fees or permits are required then.

yes or no

grade12

language science

writing-strategies

Sentences, fragments, and run-ons

Identify sentence fragments

A sentence is a group of words that expresses a complete thought. The band I'm in has been rehearsing daily because we have a concert in two weeks. A sentence fragment is a group of words that does not express a complete thought. Rehearsing daily because we have a concert in two weeks. This fragment is missing a subject. It doesn't tell who is rehearsing. The band I'm in. This fragment is missing a verb. It doesn't tell what the band I'm in is doing. Because we have a concert in two weeks. This fragment is missing an independent clause. It doesn't tell what happened because of the concert.

There is a sentence fragment that does not express a complete thought. Spring and fall—the best times to enjoy the lake and avoid the crowds of summer. No fees or permits are required then. Here is one way to fix the sentence fragment: Spring and fall are the best times to enjoy the lake and avoid the crowds of summer. No fees or permits are required then.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade8

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

Each particle in sample A has more mass than each particle in sample B. The particles in sample A also have a higher average speed than the particles in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

Which change best matches the sentence? A large amount of rock and soil tumbles down a slope.

closed choice

grade3

natural science

earth-science

Earth events

Classify changes to Earth's surface II