Question: Which of the following could Gordon's test show?

Choices:
- if the spacecraft was damaged when using a parachute with a 1 m vent going 200 km per hour
- how steady a parachute with a 1 m vent was at 200 km per hour
- whether a parachute with a 1 m vent would swing too much at 400 km per hour

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.

Gordon was an aerospace engineer who was developing a parachute for a spacecraft that would land on Mars. He needed to add a vent at the center of the parachute so the spacecraft would land smoothly. However, the spacecraft would have to travel at a high speed before landing. If the vent was too big or too small, the parachute might swing wildly at this speed. The movement could damage the spacecraft.
So, to help decide how big the vent should be, Gordon put a parachute with a 1 m vent in a wind tunnel. The wind tunnel made it seem like the parachute was moving at 200 km per hour. He observed the parachute to see how much it swung.
Figure: a spacecraft's parachute in a wind tunnel.

natural science

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.


Question: What is the name of the colony shown?

Choices:
- Maryland
- New Hampshire
- Rhode Island
- Vermont

social science

Solution:
The colony is New Hampshire.
During the colonial era, New Hampshire and New York both claimed the territory that would later become the state of Vermont. Vermont was never its own colony.


Question: Which of these organisms contains matter that was once part of the lichen?

Choices:
- bilberry
- mushroom

Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

natural science

A food web is a model.
A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating.
An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web.
An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Solution:
Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows that starts from the lichen.
No arrow points to the bilberry. So, in this food web, matter does not move from the lichen to the bilberry.


Question: What is the expected ratio of offspring with a woolly fleece to offspring with a hairy fleece? Choose the most likely ratio.

Choices:
- 0:4
- 4:0
- 2:2
- 1:3
- 3:1

This passage describes the fleece type trait in sheep:
The fleece, or outer coat, of a sheep is often cut off and used to make yarn for fabrics and other textiles. Woolly fleeces, which have shorter hairs, are usually used for clothing and blankets. Hairy fleeces, which have longer hairs, are usually used for carpets.
In a group of sheep, some individuals have a hairy fleece and others have a woolly fleece. In this group, the gene for the fleece type trait has two alleles. The allele for a hairy fleece (F) is dominant over the allele for a woolly fleece (f).
This Punnett square shows a cross between two sheep.

natural science

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.

Solution:
To determine how many boxes in the Punnett square represent offspring with a woolly fleece or a hairy fleece, consider whether each phenotype is the dominant or recessive allele's version of the fleece type trait. The question tells you that the F allele, which is for a hairy fleece, is dominant over the f allele, which is for a woolly fleece.
A woolly fleece is the recessive allele's version of the fleece type trait. A sheep with the recessive version of the fleece type trait must have only recessive alleles for the fleece type gene. So, offspring with a woolly fleece must have the genotype ff.
All 4 boxes in the Punnett square have the genotype ff.
A hairy fleece is the dominant allele's version of the fleece type trait. A sheep with the dominant version of the fleece type trait must have at least one dominant allele for the fleece type gene. So, offspring with a hairy fleece must have the genotype FF or Ff.
There are 0 boxes in the Punnett square with the genotype FF or Ff.
So, the expected ratio of offspring with a woolly fleece to offspring with a hairy fleece is 4:0. This means that, based on the Punnett square, this cross will always produce offspring with a woolly fleece. This cross is expected to never produce offspring with a hairy fleece.


Question: Which property do these three objects have in common?

Choices:
- shiny
- slippery
- opaque

natural science

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.

Solution:
Look at each object.
For each object, decide if it has that property.
An opaque object does not let light through. All three objects are opaque.
A slippery object is hard to hold onto or stand on. The tortoise shell and the basketball are not slippery.
A shiny object reflects a lot of light. You can usually see your reflection in a shiny object. The crown is shiny, but the basketball is not.
The property that all three objects have in common is opaque.


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

Choices:
- The magnitude of the magnetic force is the same in both pairs.
- The magnitude of the magnetic force is smaller in Pair 1.
- The magnitude of the magnetic force is smaller in Pair 2.

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 sizes and shapes.

natural science

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 using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller.

Solution:
Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The smaller the magnets, the smaller the magnitude of the magnetic force between them.
Magnet A is the same size in both pairs. But Magnet B is smaller in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is smaller in Pair 2 than in Pair 1.


Question: What is the capital of Wyoming?

Choices:
- Phoenix
- Baton Rouge
- Honolulu
- Cheyenne

social science

Solution: Cheyenne is the capital of Wyoming.


Question:
Is the following statement about our solar system true or false?
The largest planet is made mainly of ice.

Choices:
- true
- false

Use the data to answer the question below.

natural science

Analyze data to compare properties of planets

A planet's volume tells you the size of the planet.
The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.

Solution: The table tells you that Jupiter is the largest planet and that Jupiter is made mainly of gas. So, the largest planet is made mainly of gas.


Question: Which of the following organisms is the primary consumer in this food web?

Choices:
- copepod
- black crappie
- bacteria

Below is a food web from Little Rock Lake, a freshwater lake ecosystem in Wisconsin.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

natural science

A food web is a model.
A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating.
An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web.
An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Solution:
Primary consumers eat producers. So, in a food web, primary consumers have arrows pointing to them from producers.
The rotifer has an arrow pointing to it from the green algae. The green algae is a producer, so the rotifer is a primary consumer.
The copepod has an arrow pointing to it from the golden algae. The golden algae is a producer, so the copepod is a primary consumer.
The black crappie has arrows pointing to it from the water flea, the rotifer, and the shiner. None of these organisms is a produce, so the black crappie is not a primary consumer.
The bacteria have arrows pointing to them from the copepod and the shiner. Neither the copepod nor the shiner is a producer, so the bacteria are not primary consumers.


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

Choices:
- The magnetic force is stronger in Pair 2.
- The magnetic force is stronger in Pair 1.
- The strength of the magnetic force is the same in both pairs.

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.

natural science

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.

Solution:
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.


Question: Which better describes the Daintree rain forest ecosystem?

Choices:
- It has year-round rain. It also has soil that is poor in nutrients.
- It has cold winters. It also has many different types of organisms.

Figure: Daintree rain forest.
The Daintree rain forest is a tropical rain forest ecosystem in northeastern Australia.

natural science

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

Solution: A tropical rain forest is a type of ecosystem. Tropical rain forests have the following features: year-round rain and warm temperatures, soil that is poor in nutrients, and many different types of organisms. So, the Daintree rain forest has year-round rain. It also has soil that is poor in nutrients.


Question: What is the capital of Delaware?

Choices:
- Montpelier
- Trenton
- Dover
- Georgetown

social science

Identify state capitals of the Northeast

Solution: Dover is the capital of Delaware.


Question: Which of these states is farthest north?

Choices:
- Maine
- South Carolina
- Kansas
- Delaware

social science

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.

Solution: To find the answer, look at the compass rose. Look at which way the north arrow is pointing. Maine is farthest north.


Question: What can Greta and Allie trade to each get what they want?

Choices:
- Greta can trade her tomatoes for Allie's sandwich.
- Allie can trade her broccoli for Greta's oranges.
- Allie can trade her almonds for Greta's tomatoes.
- Greta can trade her tomatoes for Allie's broccoli.

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.
Greta and Allie open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Greta wanted broccoli in her lunch and Allie was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.

social science

Solution:
Greta wanted broccoli in her lunch and Allie was hoping for tomatoes. Look at the labeled part of the images.
Greta has tomatoes. Allie 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.


Question: What is the capital of Colorado?

Choices:
- Boulder
- Phoenix
- Colorado Springs
- Denver

social science

Solution: Denver is the capital of Colorado.


Question: Which continent is highlighted?

Choices:
- Africa
- North America
- South America
- Asia

social science

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

Solution: This continent is Asia.


Question: Identify the question that Chase's experiment can best answer.

Choices:
- Do cardinals eat more seeds per visit from feeders containing sunflower seeds compared to feeders containing flax seeds?
- Do cardinals visit feeders containing sunflower seeds more often than feeders containing flax seeds?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Chase set up five pairs of platform bird feeders around his yard. He filled one feeder in each pair with sunflower seeds and the other feeder with flax seeds. For one week, Chase watched cardinals visiting the feeders during the same hour each morning. During his observations, Chase counted the number of visits by cardinals to feeders with sunflower seeds and the number of visits by cardinals to feeders with flax seeds.
Figure: a cardinal visiting a platform feeder with sunflower seeds.

natural science

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?


Question: Which material is this path made of?

Choices:
- plastic
- brick

natural science

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

Solution:
Look at the picture of the path.
The path is made of bricks.


Question: Select the bird below.

Choices:
- cane toad
- ostrich

Birds have feathers, two wings, and a beak. A robin is an example of a bird.

natural science

Identify mammals, birds, fish, reptiles, and amphibians

Birds, mammals, fish, reptiles, and amphibians are groups of animals. The animals in each group have traits in common.
Scientists sort animals into groups based on traits they have in common. This process is called classification.

Solution:
An ostrich is a bird. It has feathers, two wings, and a beak.
The ostrich is the largest bird alive today. Ostriches cannot fly, but they can run very fast.
A cane toad is an amphibian. It has moist skin and begins its life in water.
Toads do not have teeth! They swallow their food whole.


Question: Which property do these three objects have in common?

Choices:
- blue
- hard
- sticky

natural science

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups.

Solution:
Look at each object.
For each object, decide if it has that property.
A sticky object can attach or stick to other things. The toothpaste is sticky, but the soccer shorts and the water slide are not.
Blue is a color.
This color is blue. All three objects are blue.
A hard object does not change shape when pressed or squeezed. The water slide is hard, but the toothpaste and the soccer shorts are not.
The property that all three objects have in common is blue.


Question: Which of the following was a dependent variable in this experiment?

Choices:
- the temperature of the heating pad
- the number of days until a seed germinated

The passage below describes an experiment. Read the passage and think about the variables that are described.

Kenneth wanted to grow cucumbers from seeds. He read that using a heating pad to heat up potting soil could help make seeds germinate, or sprout, faster. Kenneth wondered whether the temperature of the heating pad would affect how quickly the seeds germinated.
Kenneth prepared two potting trays, each made up of ten small pots of soil. He planted one cucumber seed in each small pot and arranged the potting trays near a sunny window. He set an electric heating pad to 75°F and placed it under one potting tray. He set a second heating pad to 85°F and placed it under the other potting tray. Kenneth observed the pots daily, and he counted the number of days it took until a seed germinated in each pot.
Hint: An independent variable is a variable whose effect you are investigating. A dependent variable is a variable that you measure.
Figure: germinating plants in a potting tray.

natural science

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.


Question: What is the capital of Mississippi?

Choices:
- Detroit
- Jackson
- Biloxi
- Topeka

social science

Identify state capitals of the Southeast

Solution: Jackson is the capital of Mississippi.


Question: Which property matches this object?

Choices:
- stretchy
- blue

natural science

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

Solution:
Look at the object.
Think about each property.
Blue is a color.
This color is blue. The melted marshmallow is not blue.
A stretchy object gets longer when you pull on it. The melted marshmallow is stretchy.


Question: Is Rafflesia arnoldii made up of many cells?

Choices:
- yes
- no

This organism is Rafflesia arnoldii. It is a member of the plant kingdom.
Rafflesia arnoldii has the largest flowers in the world. A single flower can be three feet wide! R. arnoldii is commonly called a corpse flower because the flower smells like rotting meat.

natural science

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

Solution: Rafflesia arnoldii is a plant. Plants are made up of many cells.


Question: What is the expected ratio of offspring with smooth fruit to offspring with fuzzy fruit? Choose the most likely ratio.

Choices:
- 3:1
- 2:2
- 1:3
- 4:0
- 0:4

In a group of tomato plants, some individuals have smooth fruit and others have fuzzy fruit. In this group, the gene for the fruit texture trait has two alleles. The allele for smooth fruit (F) is dominant over the allele for fuzzy fruit (f).
This Punnett square shows a cross between two tomato plants.

natural science

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.

Solution:
To determine how many boxes in the Punnett square represent offspring with smooth fruit or fuzzy fruit, consider whether each phenotype is the dominant or recessive allele's version of the fruit texture trait. The question tells you that the F allele, which is for smooth fruit, is dominant over the f allele, which is for fuzzy fruit.
Smooth fruit is the dominant allele's version of the fruit texture trait. A tomato plant with the dominant version of the fruit texture trait must have at least one dominant allele for the fruit texture gene. So, offspring with smooth fruit must have the genotype FF or Ff.
All 4 boxes in the Punnett square have the genotype FF or Ff.
Fuzzy fruit is the recessive allele's version of the fruit texture trait. A tomato plant with the recessive version of the fruit texture trait must have only recessive alleles for the fruit texture gene. So, offspring with fuzzy fruit must have the genotype ff.
There are 0 boxes in the Punnett square with the genotype ff.
So, the expected ratio of offspring with smooth fruit to offspring with fuzzy fruit is 4:0. This means that, based on the Punnett square, this cross will always produce offspring with smooth fruit. This cross is expected to never produce offspring with fuzzy fruit.


Question: Which of the following could Cooper's test show?

Choices:
- if at least 20% of the park would be shaded by trees in each design
- which design would have the least traffic noise in the concert area
- which design would have the greatest distance between the concert area and the road

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.

Cooper 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. Cooper 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.

natural science

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.


Question: Will these magnets attract or repel each other?

Choices:
- repel
- attract

natural science

Magnets can pull or push on other magnets without touching them. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes are called magnetic forces.
Magnetic forces are strongest at the magnets' poles, or ends. Every magnet has two poles: a north pole (N) and a south pole (S).
Here are some examples of magnets. Their poles are shown in different colors and labeled.
Whether a magnet attracts or repels other magnets depends on the positions of its poles.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.

Solution:
To predict if these magnets will attract or repel, look at which poles are closest to each other.
The south pole of one magnet is closest to the south pole of the other magnet. Like poles repel. So, these magnets will repel each other.


Question: What is the capital of Connecticut?

Choices:
- Hartford
- Annapolis
- New Haven
- Dover

social science

Identify state capitals of the Northeast

Solution: Hartford is the capital of Connecticut.


Question: Which ocean is highlighted?

Choices:
- the Indian Ocean
- the Atlantic Ocean
- the Pacific Ocean
- the Southern Ocean

social science

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

Solution: This is the Indian Ocean.


Question: Which statement describes the Yasuni National Park ecosystem?

Choices:
- It has mostly small plants.
- It has many different types of organisms.
- It has soil that is rich in nutrients.

Figure: Yasuni National Park.
The Amazon rain forest in South America is the largest rain forest ecosystem in the world. Ecuador's Yasuni National Park, which is in the Amazon rain forest, has many different species of plants, birds, and mammals.

natural science

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

Solution: A tropical rain forest is a type of ecosystem. Tropical rain forests have the following features: year-round rain and warm temperatures, soil that is poor in nutrients, and many different types of organisms. So, the following statement describes the Yasuni National Park ecosystem: year-round rain and warm temperatures, soil that is poor in nutrients, and many different types of organisms. It has many different types of organisms. The following statements do not describe Yasuni National Park: year-round rain and warm temperatures, soil that is poor in nutrients, and many different types of organisms. It has mostly small plants. It has soil that is rich in nutrients.


Question: Which property do these three objects have in common?

Choices:
- fragile
- bouncy
- yellow

natural science

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.

Solution:
Look at each object.
For each object, decide if it has that property.
A fragile object will break into pieces if you drop it. All three objects are fragile.
Yellow is a color.
This color is yellow. None of the objects are yellow.
A bouncy object will bounce back from the floor if you drop it. None of the objects are bouncy.
The property that all three objects have in common is fragile.


Question: Look at the models of molecules below. Select the elementary substance.

Choices:
- carbon tetrachloride
- acetaldehyde
- bromine

natural science

Identify 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.


Question: Select the organism in the same species as the pink-backed pelican.

Choices:
- Balearica pavonina
- Tyto alba
- Pelecanus rufescens

This organism is a pink-backed pelican. Its scientific name is Pelecanus rufescens.

natural science

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.

Solution:
A pink-backed pelican's scientific name is Pelecanus rufescens.
Pelecanus rufescens has the same scientific name as a pink-backed pelican. So, these organisms are in the same species.
Balearica pavonina does not have the same scientific name as a pink-backed pelican. So, Pelecanus rufescens and Balearica pavonina are not in the same species.
Tyto alba does not have the same scientific name as a pink-backed pelican. So, Pelecanus rufescens and Tyto alba are not in the same species.


Question: What is the capital of North Dakota?

Choices:
- Des Moines
- Bismarck
- Madison
- Fargo

social science

Solution: Bismarck is the capital of North Dakota.


Question: Identify the question that Jeremiah's experiment can best answer.

Choices:
- Do cardinals visit feeders containing sunflower seeds more often than feeders containing flax seeds?
- Do cardinals eat more seeds per visit from feeders containing sunflower seeds compared to feeders containing flax seeds?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Jeremiah set up five pairs of platform bird feeders around his yard. He filled one feeder in each pair with sunflower seeds and the other feeder with flax seeds. For one week, Jeremiah watched cardinals visiting the feeders during the same hour each morning. During his observations, Jeremiah counted the number of visits by cardinals to feeders with sunflower seeds and the number of visits by cardinals to feeders with flax seeds.
Figure: a cardinal visiting a platform feeder with sunflower seeds.

natural science

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?


Question: What is the capital of Massachusetts?

Choices:
- Cambridge
- Plymouth
- Boston
- Dover

social science

Identify state capitals of the Northeast

Solution: Boston is the capital of Massachusetts.


Question: Which animal is also adapted to be camouflaged in the snow?

Choices:
- short-tailed weasel
- common hawk-cuckoo

Arctic wolves live in the Canadian Arctic and Greenland. The  is adapted to be camouflaged in the snow.
Figure: Arctic wolf.

natural science

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.

Solution:
Look at the picture of the Arctic wolf.
This Arctic wolf has white fur covering its body. It is adapted to be camouflaged in the snow. The word camouflage means to blend in.
Now look at each animal. Figure out which animal has a similar adaptation.
During the winter, the short-tailed weasel has white fur covering its body. It is adapted to be camouflaged in the snow.
The common hawk-cuckoo has a gray head, a gray-and-brown back, and a white belly with a gray-and-brown pattern. It is not adapted to be camouflaged in the snow.


Question: Select the organism in the same genus as the Goliath heron.

Choices:
- Falco sparverius
- Ardea herodias
- Tigrisoma mexicanum

This organism is a Goliath heron. Its scientific name is Ardea goliath.

natural science

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.

Solution:
A Goliath heron's scientific name is Ardea goliath. The first word of its scientific name is Ardea.
Ardea herodias is in the genus Ardea. The first word of its scientific name is Ardea. So, Ardea herodias and Ardea goliath are in the same genus.
Falco sparverius is in the genus Falco. The first word of its scientific name is Falco. So, Falco sparverius and Ardea goliath are not in the same genus.
Tigrisoma mexicanum is in the genus Tigrisoma. The first word of its scientific name is Tigrisoma. So, Tigrisoma mexicanum and Ardea goliath are not in the same genus.


Question: Which country is highlighted?

Choices:
- Barbados
- the Dominican Republic
- Saint Lucia
- Saint Vincent and the Grenadines

social science

Identify and select countries of the Caribbean

Solution: This country is Saint Lucia.


Question: Will these magnets attract or repel each other?

Choices:
- repel
- attract

natural science

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: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.

Solution:
To predict if these magnets will attract or repel, 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. Opposite poles attract. So, these magnets will attract each other.


Question: Can Fromia monilis cells make their own food?

Choices:
- yes
- no

This organism is Fromia monilis. It is a member of the animal kingdom.
Fromia monilis is commonly called a tile sea star. Did you notice that this tile sea star is missing one of its arms? If a tile sea star loses an arm, it can regrow the arm over time. This ability is called regeneration.

natural science

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

Solution: Fromia monilis is an animal. Animal cells cannot make their own food. Animals get their food by digesting other organisms.


Question: Does this passage describe the weather or the climate?

Choices:
- weather
- climate

Figure: Tambor Beach, Costa Rica.
Tambor Beach is located in Costa Rica, a country in Central America. A temperature of 84°F was measured at Tambor Beach on Friday.
Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.

natural science

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.

Solution:
Read the passage carefully.
Tambor Beach is located in Costa Rica, a country in Central America. A temperature of 84°F was measured at Tambor Beach on Friday.
The underlined part of the passage tells you about the temperature at Tambor Beach on Friday. This passage describes the atmosphere at a certain place and time. So, this passage describes the weather.


Question: Which country is highlighted?

Choices:
- Vanuatu
- Tonga
- the Marshall Islands
- Nauru

social science

Identify and select countries of Oceania

Solution: This country is Nauru.


Question: Which rhetorical appeal is primarily used in this ad?

Choices:
- logos (reason)
- pathos (emotion)
- ethos (character)

language science

Identify appeals to ethos, pathos, and logos in advertisements

The purpose of an advertisement is to persuade people to do something. To accomplish this purpose, advertisements use three types of persuasive strategies, or appeals.
Appeals to ethos, or character, show the writer or speaker as trustworthy, authoritative, or sharing important values with the audience. An ad that appeals to ethos might do one of the following:
say that a brand has been trusted for many years
include an endorsement from a respected organization, such as the American Dental Association
feature a testimonial from a "real person" who shares the audience's values
use an admired celebrity or athlete as a spokesperson
Appeals to logos, or reason, use logic and verifiable evidence. An ad that appeals to logos might do one of the following:
use graphs or charts to display information
cite results of clinical trials or independently conducted studies
explain the science behind a product or service
emphasize that the product is a financially wise choice
anticipate and refute potential counterclaims
Appeals to pathos, or emotion, use feelings rather than facts to persuade the audience. An ad that appeals to pathos might do one of the following:
trigger a fear, such as the fear of embarrassment
appeal to a desire, such as the desire to appear attractive
link the product to a positive feeling, such as adventure, love, or luxury

Solution: The ad appeals to pathos, or emotion, by evoking feelings of parental love and concern.


Question: Which animal is also adapted to be camouflaged among dead leaves?

Choices:
- strawberry poison frog
- Surinam horned frog

Orange oakleaf butterflies live in the forests of Asia. This butterfly is adapted to be camouflaged among dead leaves.
Figure: orange oakleaf butterfly.

natural science

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.

Solution:
Look at the picture of the orange oakleaf butterfly.
The orange oakleaf butterfly has a brown leaf-shaped body. It is adapted to be camouflaged among dead leaves, which often have a reddish or brownish color. The word camouflage means to blend in.
Now look at each animal. Figure out which animal has a similar adaptation.
The Surinam horned frog has orange-and-brown skin. It is adapted to be camouflaged among dead leaves, which often have a reddish or brownish color.
The strawberry poison frog has brightly colored skin. It is not adapted to be camouflaged among dead leaves.


Question: Identify the question that Helen's experiment can best answer.

Choices:
- Does fabric turn darker when soaked in a mixture of black dye and water for 15 minutes compared to 30 minutes?
- Does linen fabric turn darker than cotton fabric when soaked in a mixture of black dye and water?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Helen prepared ten buckets, each with one gallon of boiling water and three tablespoons of black fabric dye. Helen soaked white linen fabric squares in five of the buckets, and white cotton fabric squares in the other five buckets. All of the fabric squares were soaked for 15 minutes. After the fabric dried, Helen scored the darkness of the squares on a scale from light to dark. She compared the darkness of the linen fabric to the darkness of the cotton fabric.
Figure: fabric that has been dyed black.

natural science

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?


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

Choices:
- The magnetic force is stronger in Pair 1.
- The magnetic force is stronger in Pair 2.
- The strength of the magnetic force is the same in both pairs.

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.

natural science

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.

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


Question: What is the capital of Washington?

Choices:
- Olympia
- Burlington
- Seattle
- Spokane

social science

Solution: Olympia is the capital of Washington.


Question: Which solution has a higher concentration of green particles?

Choices:
- Solution B
- neither; their concentrations are the same
- Solution A

The diagram below is a model of two solutions. Each green ball represents one particle of solute.

natural science

A solution is made up of two or more substances that are completely mixed. In a solution, solute particles are mixed into a solvent. The solute cannot be separated from the solvent by a filter. For example, if you stir a spoonful of salt into a cup of water, the salt will mix into the water to make a saltwater solution. In this case, the salt is the solute. The water is the solvent.
The concentration of a solute in a solution is a measure of the ratio of solute to solvent. Concentration can be described in terms of particles of solute per volume of solvent.
concentration = particles of solute / volume of solvent

Solution:
In Solution A and Solution B, the green particles represent the solute. To figure out which solution has a higher concentration of green particles, look at both the number of green particles and the volume of the solvent in each container.
Use the concentration formula to find the number of green particles per milliliter.
Solution A and Solution B have the same number of green particles per milliliter. So, their concentrations are the same.


Question: Which is this organism's scientific name?

Choices:
- comet moth
- Argema mittrei

This organism is a comet moth. It is also called Argema mittrei.

natural science

An organism's common name is the name that people normally call the organism. Common names often contain words you know.
An organism's scientific name is the name scientists use to identify the organism. Scientific names often contain words that are not used in everyday English.
Scientific names are written in italics, but common names are usually not. The first word of the scientific name is capitalized, and the second word is not. For example, the common name of the animal below is giant panda. Its scientific name is Ailuropoda melanoleuca.

Solution:
Argema mittrei is written in italics. The first word is capitalized, and the second word is not.
So, Argema mittrei is the scientific name.


Question: Which property do these three objects have in common?

Choices:
- smooth
- stretchy
- fuzzy

natural science

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups.

Solution:
Look at each object.
For each object, decide if it has that property.
A fuzzy object is covered in soft hair. None of the objects are fuzzy.
A smooth object is not scratchy or rough. All three objects are smooth.
A stretchy object gets longer when you pull on it. None of the objects are stretchy.
The property that all three objects have in common is smooth.


Question: Which continent is highlighted?

Choices:
- North America
- Africa
- Asia

social science

A continent is one of the seven largest areas of land on earth.

Solution: This continent is Asia.


Question: Which of these states is farthest north?

Choices:
- Florida
- Illinois
- Ohio
- New Hampshire

social science

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.

Solution: To find the answer, look at the compass rose. Look at which way the north arrow is pointing. New Hampshire is farthest north.


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

Choices:
- The magnitude of the magnetic force is smaller in Pair 2.
- The magnitude of the magnetic force is smaller in Pair 1.
- The magnitude of the magnetic force is the same in both pairs.

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.

natural science

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.

Solution:
The magnets in Pair 1 attract. The magnets in Pair 2 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force.
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.


Question: Which animal's legs are also adapted for wading?

Choices:
- kookaburra
- Eurasian spoonbill

Flamingos live near marshes, rivers, and oceans. They eat small crustaceans that live in shallow water. Flamingos get their food by walking through water, or wading.
The 's legs are adapted for wading. They are lightweight and keep the bird's body above the water.
Figure: flamingo.

natural science

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
Arms, legs, flippers, and wings are different types of limbs. The type of limbs an animal has is an example of an adaptation. Animals' limbs can be adapted in different ways. For example, long legs might help an animal run fast. Flippers might help an animal swim. Wings might help an animal fly.

Solution:
Look at the picture of the flamingo.
Long legs help the flamingo keep its body above the surface of the water while wading. Thin legs are easier to move through the water.
Now look at each animal. Figure out which animal has a similar adaptation.
The Eurasian spoonbill has long, thin legs. Its legs are adapted for wading.
The kookaburra has short legs. Its legs are not adapted for wading. The kookaburra uses its legs to walk and perch.


Question: Which rock is more likely to form from sediment deposited in a desert?

Choices:
- Sandstone forms from layers of sand.
- Shale forms from layers of mud.

This picture shows a desert in Asia. A desert is an environment that does not get much rain or snow.

natural science

Material that is carried by wind, water, or ice is called sediment. Sand and mud are examples of sediment. Sediment may be deposited, or laid down, in places such as deserts and the ocean floor.
Over time, sediment can be pressed together to form sedimentary rock. You can observe a sedimentary rock to learn about the environment in which the sediment was deposited.
Each type of sediment forms a different sedimentary rock. Here are some examples of sedimentary rocks:
Sandstone forms from sand. Sand is usually deposited by wind in deserts and by water on beaches.
Shale and mudstone form from mud. Mud is often deposited at the bottom of oceans and deep lakes.
Limestone forms from sediment made mostly of the shells of marine organisms. This type of sediment is often deposited in the ocean near coral reefs.
Conglomerate forms from sediment of many different sizes, such as mud, sand, pebbles, and boulders. This type of sediment is usually carried by glaciers and fast-flowing rivers. The sediment can be deposited when a glacier melts or a river starts moving more slowly.

Solution:
Sandstone is likely to form from sediment deposited in a desert.
Shale forms from layers of mud. Mud is usually deposited by water. Since deserts are dry environments, mud is rarely found in deserts.


Question: As Rusty pulls on the toy, what is the direction of the opposing force?

Choices:
- away from Coco
- toward Coco

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.
Two dogs, Rusty and Coco, play with a toy. Think about two of the forces that act on the toy:
Coco pulls toward herself.
Rusty pulls away from Coco.

natural science

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.

Solution:
Find the direction Rusty pulls on the toy.
Two dogs, Rusty and Coco, play with a toy. Think about two of the forces that act on the toy:
Coco pulls toward herself.
Rusty pulls away from Coco.
The text tells you that Rusty pulls away from Coco. The opposite direction is toward Coco. So, the direction of the opposing force is toward Coco.


Question: What is the capital of Hawaii?

Choices:
- Portland
- Bismarck
- Honolulu
- Juneau

social science

Solution: Honolulu is the capital of Hawaii.


Question: What is the capital of Washington?

Choices:
- Santa Fe
- Lansing
- Olympia
- Seattle

social science

Solution: Olympia is the capital of Washington.


Question: What is the probability that an American curl cat produced by this cross will be homozygous dominant for the ear type gene?

Choices:
- 0/4
- 2/4
- 4/4
- 3/4
- 1/4

In a group of American curl cats, some individuals have curled ears and others have straight ears. In this group, the gene for the ear type trait has two alleles. The allele for curled ears (E) is dominant over the allele for straight ears (e).
This Punnett square shows a cross between two American curl cats.

natural science

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


Question: What is the capital of Oklahoma?

Choices:
- Boise
- Oklahoma City
- Little Rock
- Birmingham

social science

Identify state capitals of the Southeast

Solution: Oklahoma City is the capital of Oklahoma.


Question: Identify the question that Jaden and Ron's experiment can best answer.

Choices:
- Do ping pong balls travel farther when launched from a 30° angle compared to a 45° angle?
- Do ping pong balls stop rolling along the ground sooner after being launched from a 30° angle or a 45° angle?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Jaden placed a ping pong ball in a catapult, pulled the catapult's arm back to a 45° angle, and launched the ball. Then, Jaden launched another ping pong ball, this time pulling the catapult's arm back to a 30° angle. With each launch, his friend Ron measured the distance between the catapult and the place where the ball hit the ground. Jaden and Ron repeated the launches with ping pong balls in four more identical catapults. They compared the distances the balls traveled when launched from a 45° angle to the distances the balls traveled when launched from a 30° angle.
Figure: a catapult for launching ping pong balls.

natural science

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?


Question:
Complete the statement.
Hydrogen is ().

Choices:
- an elementary substance
- a compound

The model below represents a molecule of hydrogen. Hydrogen gas was once used to make large airships, such as blimps, float. It is no longer used in airships because it catches fire easily.

natural science

Classify elementary substances and compounds using models

All substances are 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 chemical element boron is B, and the symbol for the chemical element chlorine is Cl.
Scientists can use models to represent molecules. A ball-and-stick model of a molecule is shown below. This model represents a molecule of the compound boron trichloride.
In a ball-and-stick model, the balls represent atoms, and the sticks represent chemical bonds. Notice how each ball is labeled with a symbol for a chemical element. The ball represents one atom of that element.

Solution:
Count the number of chemical elements represented in the model. Then, decide if hydrogen is an elementary substance or a compound.
In this model, both balls are labeled with H. So, the model shows you that hydrogen is made of one chemical element.
Substances made of only one chemical element are elementary substances. So, hydrogen is an elementary substance.


Question: What is the name of the colony shown?

Choices:
- New Jersey
- South Carolina
- West Virginia
- Rhode Island

social science

Solution: The colony is South Carolina.


Question: What is the capital of Kansas?

Choices:
- Des Moines
- Wichita
- Topeka
- Lincoln

social science

Solution: Topeka is the capital of Kansas.


Question: Which continent is highlighted?

Choices:
- North America
- Africa
- Asia
- South America

social science

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

Solution: This continent is Africa.


Question: Identify the question that Linda and Bob's experiment can best answer.

Choices:
- Does Linda's snowboard slide down a hill in less time when it has a thin layer of wax or a thick layer of wax?
- Does Linda's snowboard slide down a hill in less time when it has a layer of wax or when it does not have a layer of wax?

The passage below describes an experiment. Read the passage and then follow the instructions below.

Linda 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 Bob timed each ride. Linda and Bob 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.

natural science

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?


Question: What is the capital of Nevada?

Choices:
- Sacramento
- Las Vegas
- Carson City
- Jefferson City

social science

Solution: Carson City is the capital of Nevada.


Question: What is the name of the colony shown?

Choices:
- Maine
- Maryland
- New Hampshire
- North Carolina

social science

Solution: The colony is Maryland.


Question: What is the capital of New Mexico?

Choices:
- Albuquerque
- Santa Fe
- Honolulu
- Boston

social science

Solution: Santa Fe is the capital of New Mexico.


Question: Which continent is highlighted?

Choices:
- Europe
- Asia
- South America
- Australia

social science

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

Solution: This continent is South America.


Question: Will these magnets attract or repel each other?

Choices:
- repel
- attract

natural science

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: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.

Solution:
To predict if these magnets will attract or repel, look at which poles are closest to each other.
The north pole of one magnet is closest to the north pole of the other magnet. Like poles repel. So, these magnets will repel each other.


Question: Which animal's limbs are also adapted for climbing trees?

Choices:
- three-toed sloth
- sea turtle

Chimpanzees live in the forests of Central Africa. Their limbs are adapted for climbing trees.
Figure: chimpanzee.

natural science

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
Arms, legs, flippers, and wings are different types of limbs. The type of limbs an animal has is an example of an adaptation. Animals' limbs can be adapted in different ways. For example, long legs might help an animal run fast. Flippers might help an animal swim. Wings might help an animal fly.

Solution:
Look at the picture of the chimpanzee.
The chimpanzee uses its long limbs to reach branches while climbing. It uses its fingers and toes to grab the branches.
Now look at each animal. Figure out which animal has a similar adaptation.
The three-toed sloth has long limbs with fingers and toes. Its limbs are adapted for climbing trees.
The sea turtle has flippers. Its limbs are not adapted for climbing trees. The sea turtle uses its flippers to swim underwater.


Question: Which type of relationship is formed when a rat tapeworm attaches itself to a rat's intestine?

Choices:
- parasitic
- mutualistic
- commensal

Read the passage. Then answer the question.

A rat tapeworm is a type of flatworm that can live inside a rat's body. When a rat eats an insect that has a tapeworm inside it, the insect is digested, but the tapeworm remains alive.
The tapeworm is moved into the rat's intestines and uses suckers to attach itself to the intestine wall. Inside the rat's intestine, the tapeworm absorbs nutrients from food that the rat has eaten. If the rat has many tapeworms in its intestines, it will become weak from lack of nutrients.
Figure: a tapeworm attached to the wall of an intestine.

natural science

When two organisms of different species interact in a way that affects one or both organisms, they form a symbiotic relationship. The word symbiosis comes from a Greek word that means living together. Scientists define types of symbiotic relationships based on how each organism is affected.
This table lists three common types of symbiotic relationships. It shows how each organism is affected in each type of symbiotic relationship.
Type of symbiotic relationship | Organism of one species... | Organism of the other species...
Commensal | benefits | is not significantly affected
Mutualistic | benefits | benefits
Parasitic | benefits | is harmed (but not usually killed)

Solution:
When a rat tapeworm attaches itself to a rat's intestine, the tapeworm gets nutrients that it needs to grow and survive. So, the tapeworm benefits from its relationship with the rat.
The rat loses nutrients from its food to the tapeworm. So, the rat is harmed by its relationship with the tapeworm.
Since the tapeworm benefits and the rat is harmed, a parasitic relationship is formed when a rat tapeworm attaches itself to the intestine of a rat.


Question: What is the capital of California?

Choices:
- San Francisco
- Sacramento
- Jefferson City
- Lansing

social science

Solution: Sacramento is the capital of California.


Question: Which property do these three objects have in common?

Choices:
- salty
- scratchy
- sticky

natural science

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.

Solution:
Look at each object.
For each object, decide if it has that property.
Potato chips have a salty taste. The honey and the chocolate milkshake are not salty.
A sticky object can attach or stick to other things. All three objects are sticky.
A scratchy object is rough and itchy against your skin. None of the objects are scratchy.
The property that all three objects have in common is sticky.


Question: Based on the arrows, which of the following living things is a decomposer?

Choices:
- kelp
- bat star

Below is a food web from an ocean ecosystem. The ecosystem is in Monterey Bay, off the coast of California.
A food web is a model that shows how the matter eaten by living things moves through an ecosystem. The arrows show how matter moves through the food web.

natural science

A food web is a model.
Models can make things in nature easier to understand. Models can be simpler than the things they represent. A food web is a model that shows where living things in an ecosystem get their food. If a food web showed every living thing in an ecosystem, the food web would be hard to understand. So, each food web shows how some living things in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one living thing to another. Each arrow shows the direction that matter moves when one living thing eats another living thing. An arrow starts from the living thing that is eaten. The arrow points to the living thing that is doing the eating.
A living thing in a food web can have more than one arrow pointing from it. This shows that the living thing is eaten by more than one other living thing in the food web.
A living thing in a food web can also have more than one arrow pointing to it. This shows that the living thing eats more than one other living thing in the food web.

Solution:
Decomposers help break down dead living things into simpler matter, such as nutrients. These nutrients can then help plants and other living things grow. In a food web, there is an arrow pointing from another living thing to a decomposer. There are no arrows pointing from a decomposer to another living thing.
The kelp has an arrow pointing from it. So, the kelp is not a decomposer.
The bat star does not have arrows pointing from it to other living things. So, the bat star is a decomposer.


Question: Is marble a mineral or a rock?

Choices:
- rock
- mineral

Marble has the following properties:
naturally occurring
no fixed crystal structure
solid
dissolves in acid
not made by organisms
made mostly of calcite

natural science

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!

Solution: The properties of marble match the properties of a rock. So, marble is a rock.


Question:
Complete the statement.
Ethane is ().

Choices:
- an elementary substance
- a compound

The model below represents a molecule of ethane. Ethane is used to make plastic bags.

natural science

Classify elementary substances and compounds using models

All substances are 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 chemical element boron is B, and the symbol for the chemical element chlorine is Cl.
Scientists can use models to represent molecules. A ball-and-stick model of a molecule is shown below. This model represents a molecule of the compound boron trichloride.
In a ball-and-stick model, the balls represent atoms, and the sticks represent chemical bonds. Notice how each ball is labeled with a symbol for a chemical element. The ball represents one atom of that element.

Solution:
Count the number of chemical elements represented in the model. Then, decide if ethane is an elementary substance or a compound.
In this model, each ball is labeled with C for carbon or H for hydrogen. So, the model shows you that ethane is made of two chemical elements bonded together.
Substances made of two or more chemical elements bonded together are compounds. So, ethane is a compound.


Question: What is the capital of Rhode Island?

Choices:
- Fayetteville
- Huntington
- Providence
- Newport

social science

Identify state capitals of the Northeast

Solution: Providence is the capital of Rhode Island.


Question: Which is this organism's scientific name?

Choices:
- Gavia immer
- common loon

This organism is a common loon. It is also called Gavia immer.

natural science

An organism's common name is the name that people normally call the organism. Common names often contain words you know.
An organism's scientific name is the name scientists use to identify the organism. Scientific names often contain words that are not used in everyday English.
Scientific names are written in italics, but common names are usually not. The first word of the scientific name is capitalized, and the second word is not. For example, the common name of the animal below is giant panda. Its scientific name is Ailuropoda melanoleuca.

Solution:
Gavia immer is written in italics. The first word is capitalized, and the second word is not.
So, Gavia immer is the scientific name.


Question: Which of these states is farthest west?

Choices:
- Missouri
- Florida
- Montana
- Oregon

social science

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.

Solution: To find the answer, look at the compass rose. Look at which way the west arrow is pointing. Oregon is farthest west.


Question: Which property do these three objects have in common?

Choices:
- slippery
- transparent
- yellow

natural science

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.

Solution:
Look at each object.
For each object, decide if it has that property.
Yellow is a color.
This color is yellow. All three objects are yellow.
A slippery object is hard to hold onto or stand on. The rubber toys and the gold nugget are not slippery.
You can see clearly through a transparent object. None of the objects are transparent.
The property that all three objects have in common is yellow.


Question: Which statement describes the Cape Breton Highlands National Park ecosystem?

Choices:
- It has soil that is rich in nutrients.
- It has many evergreen trees.

Figure: Cape Breton Highlands National Park.
Cape Breton Highlands National Park is a taiga ecosystem in eastern Canada. It is mostly covered with taiga forests that are home to moose, bears, bald eagles, and other organisms.

natural science

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

Solution: A taiga is a type of ecosystem. Taigas have the following features: long, cold winters and short, cool summers, many evergreen trees, and soil that is poor in nutrients. So, the following statements describe the Cape Breton Highlands National Park ecosystem: long, cold winters and short, cool summers, many evergreen trees, and soil that is poor in nutrients. It has long, cold winters and short, cool summers. It has many evergreen trees. The following statement does not describe Cape Breton Highlands National Park: long, cold winters and short, cool summers, many evergreen trees, and soil that is poor in nutrients. It has soil that is rich in nutrients.


Question: Which of these organisms contains matter that was once part of the lichen?

Choices:
- mushroom
- short-tailed weasel
- brown lemming
- rough-legged hawk
- bilberry

Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

natural science

A food web is a model.
A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food.
Arrows show how matter moves.
A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating.
An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web.
An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Solution:
Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows that starts from the lichen.
The bilberry does not have any arrows pointing to it. So, in this food web, matter does not move from the lichen to the bilberry.There are two paths matter can take from the lichen to the mushroom: lichen->barren-ground caribou->mushroom. lichen->barren-ground caribou->grizzly bear->mushroom. brown lemming. The brown lemming has two arrows pointing to it. These arrows start from the bear sedge and the bilberry. Neither the bear sedge nor the bilberry has any arrows pointing to it. So, in this food web, matter does not move from the lichen to the brown lemming.. short-tailed weasel. The only arrow pointing to the short-tailed weasel starts from the brown lemming. The brown lemming has two arrows pointing to it. These arrows start from the bear sedge and the bilberry. Neither the bear sedge nor the bilberry has any arrows pointing to it. So, in this food web, matter does not move from the lichen to the short-tailed weasel.. rough-legged hawk. The only arrow pointing to the rough-legged hawk starts from the parasitic jaeger. The only arrow pointing to the parasitic jaeger starts from the brown lemming. The brown lemming has two arrows pointing to it. These arrows start from the bear sedge and the bilberry. Neither the bear sedge nor the bilberry has any arrows pointing to it. So, in this food web, matter does not move from the lichen to the rough-legged hawk..


Question: Will these magnets attract or repel each other?

Choices:
- attract
- repel

Two magnets are placed as shown.

Hint: Magnets that attract pull together. Magnets that repel push apart.

natural science

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.

Solution:
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 north pole of the other magnet. Poles that are the same repel. So, these magnets will repel each other.


Question: What is the name of the colony shown?

Choices:
- New Hampshire
- Vermont
- New York
- Delaware

social science

Solution:
The colony is New York.
During the colonial era, New Hampshire and New York both claimed the territory that would later become the state of Vermont. Vermont was never its own colony.


Question: Which bird's beak is also adapted to catch insects?

Choices:
- barn swallow
- hanging parrot

Common nighthawks eat insects and other small invertebrates. The shape of the 's beak is adapted to catch insects.
Figure: common nighthawk.

natural science

Animal adaptations: beaks, mouths, and necks

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks.

Solution:
Look at the picture of the common nighthawk.
A short, thin beak is light and easy to move. The common nighthawk uses its beak to grab fast-moving insects while flying.
Now look at each bird. Figure out which bird has a similar adaptation.
The barn swallow has a short, thin beak. Its beak is adapted to catch insects.
The hanging parrot has a small hooked beak. Its beak is not adapted to catch insects. The hanging parrot uses its beak to eat fruit and seeds.


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

Choices:
- neither; the samples have the same temperature
- sample A
- sample B

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.

natural science

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.

Solution:
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.


Question: What is the capital of Connecticut?

Choices:
- Columbia
- Bridgeport
- New Haven
- Hartford

social science

Identify state capitals of the Northeast

Solution: Hartford is the capital of Connecticut.


Question: What is the capital of Ohio?

Choices:
- Wilmington
- Reno
- Cleveland
- Columbus

social science

Solution: Columbus is the capital of Ohio.


Question: Is dolerite a mineral or a rock?

Choices:
- mineral
- rock

Dolerite has the following properties:
found in nature
not made by organisms
coarse-grained texture
solid
no fixed crystal structure
not a pure substance

natural science

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!

Solution: The properties of dolerite match the properties of a rock. So, dolerite is a rock.