A gardener grows a tall sunflower in a large pot all summer. When the plant is pulled up, the soil in the pot weighs almost the same as it did in the spring. Where did most of the sunflower's new material come from?

A student claims that a plant does not get most of its material from soil. Which observation best supports that claim?

A pine needle falls onto the forest floor. Over the next two years it crumbles apart until it can no longer be seen. Where does the matter that made up that needle end up?

A hawk catches and eats a snake. That snake had eaten a grasshopper, and the grasshopper had been chewing on meadow grass. Where did the energy in the hawk's meal originally come from?

In a pond, tiny green algae are eaten by small shrimp, and the shrimp are eaten by sunfish. One summer a disease kills most of the algae. What is the most likely effect on the shrimp?

Sirius looks brighter in our night sky than the star Rigel, even though Rigel gives off far more light. What best explains why Sirius looks brighter from Earth?

At night the stars look like tiny points of light, but by day the Sun looks like a huge, bright disk. The Sun is an ordinary star, about the same size as many of those points of light. What best explains why the Sun looks so much bigger to us?

A student measures a flagpole's shadow four times on the same sunny day. 8 a.m.: 240 cm. Noon: 60 cm. 2 p.m.: 140 cm. 4 p.m.: 230 cm. What do these measurements show?

Ocean waves pound a rocky sea cliff, and every year a little more of the cliff face crumbles into the water. Which interaction between Earth's parts does this show?

Prairie dogs dig long tunnels through a grassland. Their digging loosens packed dirt and mixes dead plant pieces down into it. Which two parts of the Earth system are interacting?

A summer storm drops heavy rain on a bare hillside field. The rushing runoff carries loose soil down the slope and into a creek at the bottom. What is happening in this scenario?

Almost all of the water on Earth is stored in one place. Where is it?

Only a small share of Earth's water is fresh water, and most of that fresh water is hard for people to reach. Where is most of Earth's fresh water?

A rainstorm leaves a puddle on a blacktop playground. Two hours later the blacktop is dry, because the puddle water evaporated into the air. What happens to that water next in the water cycle?

After two dry summers, a town limits lawn watering to two days a week. What problem is this rule meant to address?

A neighborhood digs a shallow planted basin at the low edge of a parking lot so rain collects there before it can rush into a nearby creek. What does this design mainly do?

True or False: A town starts picking up aluminum cans at the curb each week and sending them to be melted down into new cans. The town's goal is to cut how much new metal must be dug out of the ground. This choice will help the town meet that goal.

True or False: A logging company plants young native trees across a hillside it cleared last year, hoping to hold the loose soil in place and bring wildlife back to the slope. Because the new trees start out small, this choice cannot meet that goal.

A shallow lake warms sharply during a two-week heat wave, and the fish in it crowd around a cool spring feeding the lake. Which two of Earth's parts interact to warm the lake?

A farmer plows dead cornstalks back into a field instead of burning them. What happens to the matter in those stalks?