The early atmosphere was mainly carbon dioxide and water vapour. Water vapour condensed to form the oceans. Photosynthesis caused the amount of carbon dioxide to decrease and oxygen to increase.
Which gas was thought to be a major part of the early atmosphere?
Which of these planets has an atmosphere most similar to what scientists thought the Earth's early atmosphere was like?
In the modern day atmosphere, what is the approximate percentage of nitrogen?
The early atmosphere contained a lot more water vapour than the modern atmosphere does. Where did it go?
It escaped into space
It condensed to form the oceans
It was absorbed by plants
What biochemical process absorbs carbon dioxide from the atmosphere and replaces it with oxygen?
Which of the following is the correct word equation for photosynthesis?
glucose → carbon dioxide + ethanol
glucose + oxygen → carbon dioxide + water
carbon dioxide + water → glucose + oxygen
Which process removed carbon dioxide from the atmosphere?
Formation of igneous rocks
Formation of sedimentary rocks
Formation of metamorphic rocks
Which of the following is not a fossil fuel?
How long does it take to form fossil fuels?
Millions of years
Thousands of years
Hundreds of years
Why did nitrogen build up in the atmosphere?
It is unreactive
It is produced by respiration
It is produced by farming