Gases in the Earth's Atmosphere

What is the most abundant gas in the Earth's atmosphere?

• Nitrogen

• Oxygen

• Carbon Dioxide

• Water Vapor

What is the second most abundant gas in the Earth's atmosphere?

• Nitrogen

• Oxygen

• Carbon Dioxide

• Water Vapor

Which gas was present in small proportions in the Earth's early atmosphere?

• Argon

• Methane

• Ammonia

• All of the above

During the first billion years, what was the main gas in the Earth's atmosphere?

• Nitrogen

• Oxygen

• Carbon Dioxide

• Water Vapor

What were the two main differences between the early atmosphere and the atmosphere today?

• Higher levels of carbon dioxide and less nitrogen

• Higher levels of nitrogen and less carbon dioxide

• Higher levels of oxygen and less carbon dioxide

• Higher levels of carbon dioxide and less oxygen

What happened to the carbon dioxide in the early atmosphere?

• It dissolved in the oceans

• It formed sediments of carbonate rock

• It was used to make corals and shells

• All of the above

When did photosynthetic algae first evolve in the oceans?

• 1 billion years ago

• 2.7 billion years ago

• 4.6 billion years ago

• 200 million years ago

What did photosynthesis produce?

• Carbon Dioxide

• Water Vapor

• Oxygen

• Nitrogen

What increased the amount of oxygen in the atmosphere?

• Volcanic activity

• Formation of sedimentary rock

• Photosynthetic algae

• Evolution of plants

At what point could animals evolve due to the level of oxygen in the atmosphere?

• When the level of oxygen was very low

• When the level of oxygen was moderate

• When the level of oxygen was high

• When the level of oxygen was very high