Earth's Atmosphere Evolution (Cognito Video)

What is the current composition of the Earth's atmosphere?

• 70% nitrogen, 30% oxygen

• 80% oxygen, 20% nitrogen

• 80% nitrogen, 20% oxygen

• 50% nitrogen, 50% oxygen

What was the primary gas in the early Earth's atmosphere?

• Oxygen

• Nitrogen

• Carbon dioxide

• Methane

How did the formation of oceans affect the carbon dioxide levels in the atmosphere?

• Decreased carbon dioxide levels

• Increased carbon dioxide levels

• Had no effect on carbon dioxide levels

• Increased oxygen levels

When did algae first appear on Earth?

• 1 billion years ago

• 2.7 billion years ago

• 3.5 billion years ago

• 4.6 billion years ago

What process do algae and green plants use to reduce carbon dioxide and produce oxygen?

• Fermentation

• Combustion

• Photosynthesis

• Respiration

What happens to the carbon in algae and green plants after they die?

• It is released back into the atmosphere

• It is absorbed by other plants

• It becomes part of the sedimentary rock

• It evaporates

What type of rock is formed from thick deposits of dead plant material?

• Shale

• Sandstone

• Limestone

• Coal

What is limestone primarily made of?

• Iron oxide

• Magnesium sulfate

• Calcium carbonate

• Silicon dioxide

What is the main source of crude oil and natural gas?

• Dead plants

• Volcanic activity

• Atmospheric nitrogen

• Dead plankton

What major change allowed more complex life like animals to evolve?

• Decrease in water vapor levels

• Increase in oxygen levels

• Decrease in methane levels

• Increase in nitrogen levels