Earth’s atmosphere

Earth’s atmosphere is 21 percent _______________, 78 percent _______________, and one percent trace gases.

• oxygen, nitrogen

• nitrogen, oxygen

• carbon dioxide, oxygen

• oxygen, carbon dioxide

The ability of Earth’s atmosphere to absorb and retain heat is affected by:

• the presence of greenhouse gases

• the amount of sunlight received

• the rotation of the Earth

• the distance from the Moon

Changes in the composition of Earth’s atmosphere have been caused by:

• natural processes and human activities

• the position of the Moon

• the tilt of Earth’s axis

• the color of the oceans

What makes the Earth’s atmosphere unique:

• It contains Water

• It is composed entirely of carbon dioxide.

• It has no water vapor present.

• It is thicker than the atmospheres of all other planets.

Earth’s most primitive atmosphere may have been comprised of mainly:

• hydrogen and helium

• oxygen and nitrogen

• carbon dioxide and oxygen

• methane and ammonia

What could have prevented the early Earth from having an atmosphere at all:

• Intense solar wind stripping away gases

• Abundant volcanic outgassing

• Presence of liquid water

• Formation of a magnetic field

What are 3 gases in the Early atmosphere, that if you breathed for too long would kill you?

• CO2 (carbon dioxide), CO (carbon monoxide), SO2 (sulfur dioxide)

• O2 (oxygen), N2 (nitrogen), Ar (argon)

• H2O (water vapor), Ne (neon), He (helium)

• CH4 (methane), NH3 (ammonia), H2 (hydrogen)

Where did all these gases result from?

• Volcanic outgassing

• Photosynthesis by plants

• Comet impacts

• Human industrial activity

What was the Early photosynthetic life that consumed carbon dioxide and generated oxygen?

• Cyanobacteria (blue-green algae)

• Fungi

• Amoeba

• Paramecium

What allowed animal life to become possible?

• The generation of oxygen by early photosynthetic life

• The extinction of dinosaurs

• The formation of mountains

• The cooling of Earth's core