Which of these was the first source of oxygen in our atmosphere

A. Oxygen produced by living things on land

B. Oxygen released by volcanoes

C. Oxygen released by living cyanobacteria in the ocean which then was released into the atmosphere

D. the original accretion of the Earth

Question

Which of these was the first source of oxygen in our atmosphere

	
A. Oxygen produced by living things on land

	
B. Oxygen released by volcanoes

	
C. Oxygen released by living cyanobacteria in the ocean which then was released into the atmosphere

	
D. the original accretion of the Earth

awolflover1 · Answer

What do you think?

misssmartiez · Answer

A.

The vegetation of the earth inhales carbon, and exhales oxygen; which we breath in.

lpabc · Answer

I agree. The vegetation is the only thing that can recycle carbon dioxide and produce oxygen.