Earth's Atmosphere

Earth's current atmosphere is _?_.

• 78% nitrogen, 21% oxygen, 0.9% argon and 0.037% carbon dioxide
• 78% oxygen, 21%nitrogen, 0.9% argon, 0.037% carbon dioxide
• 78% nitrogen, 21% argon, 1% oxygen
• 78% oxygen, 21% nitrogen, 1% carbon dioxide

Earth's current atmosphere is _?_.

• 78% nitrogen, 21% oxygen, 0.9% argon and 0.037% carbon dioxide
• 78% oxygen, 21%nitrogen, 0.9% argon, 0.037% carbon dioxide
• 78% nitrogen, 21% argon, 1% oxygen
• 78% oxygen, 21% nitrogen, 1% carbon dioxide

What makes up 99% of the atmosphere?

• nitrogen
• oxygen
• carbon dioxide
• nitrogen and oxygen together

What does ozone in the atmosphere do?

• It absorbs and traps heat energy.
• It provides a place for water vapor to condense.
• It protects against harmful UV radiation.
• It helps plants grow.

As you increase in altitude, pressure _?_.

• increases
• decreases
• remains the same

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

The mixture of gases that surrounds Earth is the ______________.

• atmosphere

• air pressure

• troposphere

• stratosphere

__________ is the measure of the force with which particles in the air push on an area of a surface.

• atmosphere

• air pressure

• troposphere

• stratosphere

The _________ protects Earth by absorbing large amounts of harmful ultraviolet radiation from the sun.

• ozone layer

• mesosphere

• thermosphere

• greenhouse effect