Earth as a System

Matter and Energy in Earth's Systems

​Explanation

The correct answer is “system.” A system is a group of parts that work together as a whole. Individual components make up the parts that work together.

Multiple Choice

What provides the energy that drives the water cycle?

• heat sources at the center of the Earth

• evaporation and condensation

• heat of the sun

• biosphere

​Explanation

• ​The correct answer is “heat of the sun.”

• The heat sources at Earth’s center do not drive the water cycle, although they do set up convection currents that move the magma.

• Evaporation and condensation are results of the water cycle taking place, but they do not drive it.

• The biosphere is the collection of all living organisms, so it does not drive the water cycle.

Multiple Choice

Which phrase(s) describe the biosphere?

• holds all of Earth's water

• contains all living things on Earth

• rocks and metals

• thin envelope of gases that contains the weather

Multiple Choice

Which phrase(s) describe the atmosphere?

• holds all of Earth's water

• contains all living things on Earth

• rocks and metals

• thin envelope of gases that contains the weather

Multiple Select

Which phrase(s) describe the hydrosphere?

• holds all of Earth's water

• contains all living things on Earth

• rocks and metals

• cryosphere

Multiple Select

Which phrase(s) describe the geosphere?

• holds all of Earth's water

• contains solid inner metal core, liquid outer core, and rocky mantle and crust

• rocks and metals

• cryosphere

Explanation​

• ​The biosphere is the part of Earth containing all the living organisms.

• The hydrosphere includes all water on Earth, including the cryosphere, or frozen water.

• The geosphere is the rocks and metals found in the crust, the two cores, and the mantle.

• The atmosphere is the thin envelope of gases surrounding Earth which includes Earth’s weather and climate components.

Multiple Choice

Feedback can either cause a change in the system or keep it stable. Melting glaciers are an example of positive feedback.

Why is this considered positive feedback?

• Melting glaciers would add more water to the hydrosphere, making it wetter.

• Melting glaciers would change the land around it, speeding up erosion.

• Melting glaciers would let the uncovered air and land warm, which speeds up the melting.

• Melting glaciers would mean more ice at its top, which would slow the glaciers melting.

​Explanation

The correct answer is “Melting glaciers would let the uncovered air and land warm, which speeds up the melting.” Glaciers melting would add more water to the hydrosphere. It is not positive feedback because it doesn’t affect the glacier’s melting. Erosion might take place at a melting glacier, but it doesn’t speed up the melting. More ice at the top would not slow the glaciers melting. It wouldn’t contribute to faster melting, either.