Explain two reasons why having an oxygen-rich atmosphere is important for life on earth?

Answers

quantumclaustrophobe

It's necessary for all animal-forms of life (including us), and it replaces the greenhouse gases in the atmosphere, allowing for a more temperate climate.

Joan H

Have you tried breathing any place where there is no oxygen?

Robin

the earth is not oxygen rich its only 21%

patrick

Longer life. Better for plants

Pope

Breathing and fire.