Earth’s Spheres
Systems & Changes
Water Cycle
Carbon Cycle
Nitrogen Cycle
100

100 points — Which sphere includes Earth’s rocks and solid land?

A. Atmosphere
B. Geosphere
C. Biosphere
D. Hydrosphere

B. Geosphere

100

100 points — What is a system?

A. An object that never changes
B. A collection of unrelated objects
C. A group of parts that interact
D. A process that happens only once

C. A group of parts that interact

100

100 points — What is another name for the hydrologic cycle?

A. Carbon cycle
B. Nitrogen cycle
C. Rock cycle
D. Water cycle

D. Water cycle

100

100 points — What does the carbon cycle describe?

A. Carbon moving among Earth’s spheres
B. Water moving only through the oceans
C. Rocks remaining unchanged underground
D. Nitrogen disappearing from Earth

A. Carbon moving among Earth’s spheres

100

100 points — Which gas is the most abundant in Earth’s atmosphere?

A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Methane

B. Nitrogen

200

200 points — Which sphere includes the gases surrounding Earth?

A. Hydrosphere
B. Biosphere
C. Geosphere
D. Atmosphere

D. Atmosphere

200

200 points — What makes a process a cycle?

A. It returns to its beginning and repeats.
B. It happens once and then stops.
C. It involves only living things.
D. It always finishes in one day.

A. It returns to its beginning and repeats.

200

200 points — What happens during evaporation?

A. Water vapor changes into liquid droplets.
B. Liquid water changes into water vapor.
C. Rain falls from clouds to the ground.
D. Liquid water freezes into solid ice.

B. Liquid water changes into water vapor.

200

200 points — Which gas contains most of the carbon found in the atmosphere?

A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Hydrogen

C. Carbon dioxide

200

200 points — Which organisms help change nitrogen gas into forms plants can use?

A. Birds
B. Fish
C. Trees
D. Bacteria

D. Bacteria

300

300 points — Which example belongs to the biosphere?

A. A tree growing near a lake
B. The water in the lake
C. The rocks beside the lake
D. The air above the lake

A. A tree growing near a lake

300

300 points — Which description best explains an ecosystem?

A. Only the animals living in an area
B. Only the rocks and soil in an area
C. Only the plants living in an area
D. Organisms and their environment interacting

D. Organisms and their environment interacting

300

300 points — Water vapor cools and forms tiny liquid droplets in a cloud. Which process is happening?

A. Precipitation
B. Evaporation
C. Condensation
D. Nitrogen fixation

C. Condensation

300

300 points — How do plants get carbon to help build their body parts?

A. They turn sunlight directly into carbon.
B. They take in carbon dioxide.
C. They take in nitrogen gas.
D. They turn water directly into carbon.  


B. They take in carbon dioxide.

300

300 points — What happens during nitrogen fixation?

A. Bacteria convert nitrogen gas into ammonium.
B. Water vapor changes into liquid droplets.
C. Plants remove carbon dioxide from the air.
D. Nitrogen compounds change into nitrogen gas.

A. Bacteria convert nitrogen gas into ammonium.

400

400 points — Which list contains only examples of the hydrosphere?

A. Trees, birds, and insects
B. Rocks, mountains, and soil
C. Oceans, rivers, and glaciers
D. Oxygen, nitrogen, and other gases

C. Oceans, rivers, and glaciers

400

400 points — Which is an example of a gradual change that happens over a long time?

A. A meteorite striking Earth
B. Continents slowly moving
C. A sudden volcanic eruption
D. A sudden landslide

B. Continents slowly moving

400

400 points — Which example is precipitation?

A. Snow falling from a cloud
B. Water vapor rising from an ocean
C. Water soaking into the soil
D. A plant absorbing water through its roots

A. Snow falling from a cloud

400

400 points — Which process releases carbon back into the atmosphere?

A. Plants taking in carbon dioxide
B. Carbon dioxide dissolving in seawater
C. Carbon being stored in fossil fuels
D. Dead organisms decomposing

D. Dead organisms decomposing

400

400 points — How do animals get the nitrogen they need?

A. By absorbing sunlight
B. By breathing nitrogen gas
C. By eating plants or other animals
D. By drinking only pure water

C. By eating plants or other animals

500

500 points — A tree’s roots grow into a rock and cause it to crack. Which two spheres are interacting?

A. Atmosphere and hydrosphere
B. Biosphere and geosphere
C. Hydrosphere and biosphere
D. Geosphere and atmosphere

B. Biosphere and geosphere

500

500 points — Warming oceans release carbon dioxide. The carbon dioxide causes more warming, which releases even more carbon dioxide. What is this an example of?

A. A negative feedback mechanism that reduces change
B. A system whose parts do not interact
C. A positive feedback mechanism that increases change
D. A cycle that has completely stopped

C. A positive feedback mechanism that increases change

500

500 points — Why is water important to living organisms?

A. It stops all chemical reactions in organisms.
B. It prevents nutrients from moving through organisms.
C. It replaces every other substance organisms need.
D. It helps transport nutrients and carry away wastes.

D. It helps transport nutrients and carry away wastes.

500

500 points — What can happen when seawater becomes warmer?

A. It releases dissolved carbon dioxide into the atmosphere.
B. It changes all dissolved carbon dioxide into oxygen.
C. It stops interacting with the atmosphere.
D. It permanently traps all its dissolved carbon dioxide.

A. It releases dissolved carbon dioxide into the atmosphere.

500

500 points — Fertilizer washes from a field into a nearby river. How can this affect the nitrogen cycle?

A. It removes all nitrogen from the river.
B. It adds nitrogen compounds to the river.
C. It turns nitrogen into carbon dioxide.
D. It stops nitrogen from moving through Earth’s spheres.

B. It adds nitrogen compounds to the river.