How were large amounts of oxygen first introduced into earth's atmosphere?

a. they were deposited by comets that collided with earth.

b. they were released from the earth by erupting geysers.

c. they were produced as a byproduct of photosynthesis.

d. they were produced through atmospheric precipitation.

Question

Mcduff

23 January, 13:53

+5

Answers (2)

Know the Answer?

Rachael Benjamin · Answer 1

c. they were produced as a byproduct of photosynthesis.

Zachary Franco · Answer 2

C. They were produced as a byproduct of photosynthesis.