Which of the following is NOT one of Earth's five main systems?

• Geosphere

• Hydrosphere

• Ionosphere

• Biosphere

What percentage of Earth's water is saline (saltwater in oceans)?

• 96.5%

• 75%

• 50%

• 25%

How do glaciers in the cryosphere contribute to erosion? (We will think of the crysosphere as part of the hydrosphere.)

• By melting ice into water

• By scouring bits of rock from bedrock

• By increasing atmospheric pressure

• By promoting biodiversity

What is the primary role of the atmosphere in supporting life on Earth?

• Providing habitats for organisms

• Shielding Earth from harmful ultraviolet radiation

• Forming coal, oil, and natural gas

• Breaking down rocks into sediments

What is the term used to describe the variety of life within the biosphere?

• Abiotic factors

• Biodiversity

• Atmospheric gases

• Hydrosphere