Earth's Atmosphere

What is the most common gas in the atmosphere?

• nitrogen
• oxygen
• water vapor
• carbon dioxide

Oxygen makes up approximately ____% of the gases in the atmosphere.

• 20
• 40
• 60
• 80

What decreases with altitude throughout Earth's atmosphere?

• density
• pressure
• density and pressure
• temperature and density

What is the correct order of earth's atmospheric layers from bottom to top?

• Stratosphere, Mesosphere, Troposphere, Thermosphere, Exosphere.
• Stratosphere, Troposphere, Mesosphere, Thermosphere, Exosphere.
• Stratosphere, Troposphere, Thermosphere, Mesosphere, Exosphere.
• Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.

Why is atmospheric pressure greatest in the troposphere?

• gravity compresses the atmosphere as it pushes the gases down
• thermal and kinetic energy are the highest near the surface
• the coldest temperatures in the atmosphere are at Earth's surface
• the matter in the troposphere is the least dense

Which layer of the atmosphere has the highest density of gas molecules and highest atmospheric pressure?

• troposphere
• mesosphere
• stratosphere
• thermosphere

What is the atmospheric layer closest to the surface?

• troposphere
• stratosphere
• mesosphere
• thermosphere

Directly above the troposphere is the _________.

• stratosphere
• mesosphere
• exosphere
• thermosphere

Within the stratosphere is the ozone layer. What does the ozone layer do?

• It protects us from meteors
• It protects us from violent solar flares
• It protects us from ultra violet radiation
• It helps us breathe
  

Directly above the stratosphere is the _________.

• mesosphere
• troposphere
• thermosphere
• exosphere