Oxygen Cycle and Its Processes

What does the oxygen cycle involve?

• Movement of oxygen between living and non-living factors

• Movement of carbon dioxide

• Movement of water

• Movement of nitrogen

Where is the largest reservoir of Earth's oxygen found?

• Atmosphere

• Hydrosphere

• Biosphere

• Lithosphere

Approximately what percentage of the atmosphere is composed of oxygen?

• 21%

• 33%

• 22%

• 50%

Which process is primarily responsible for releasing oxygen into the atmosphere?

• Cellular respiration

• Decomposition

• Photosynthesis

• Combustion