Composition of the Atmosphere

Multiple Choice

Which gas is present in the highest percentage in Earth's atmosphere?

• Oxygen

• Nitrogen

• Argon

• Carbon Dioxide

Multiple Choice

Which process makes nitrogen in the atmosphere usable for humans?

• Photosynthesis by plants

• Nitrogen-fixing bacteria in the soil

• Absorption by ocean water

• Direct inhalation

Multiple Select

Which of the following contributed to changes in atmospheric composition over Earth's history?

• Volcanic activity

• Photosynthesis by plants

• Condensation of water vapor

• Formation of mountains

Open Ended

Explain how the composition of Earth's atmosphere has changed from its early history to the present day.

Fill in the Blank

A barometer is used to measure air ___ .

Multiple Choice

Why is atmospheric pressure greater at sea level than in the mountains?

• Air is warmer at sea level

• Gravity pulls more air down at sea level

• There is less air at sea level

• Mountains block air movement

Open Ended

Describe the roles of oxygen and nitrogen in the atmosphere and how they become usable for living organisms.

Multiple Choice

What is the atmosphere made of?

• Nitrogen, Oxygen, Argon, and trace gases

• Only Oxygen and Nitrogen

• Carbon dioxide and Methane

• Water vapor and Dust