Question

According to scientific evidence, earth’s earliest atmosphere lacked oxygen. Over time, oxygen was added to the atmosphere.

Which statements explain how this change occurred and how it affected life on earth?

Choose all answers that are correct.

A.
The addition of oxygen to the earth's atmosphere helped make possible the development of eukaryotic organisms, which need oxygen to carry out many of their life processes.

Answer 1

B.
When cyanobacteria evolved, they carried out photosynthesis. Oxygen is a product of photosynthesis. The addition of oxygen to earth’s atmosphere helped make possible the development of eukaryotic organisms, which need oxygen to carry out many of their life processes.

C.
The addition of oxygen to the earth's atmosphere helped make possible the development of prokaryotic organisms, which need oxygen to carry out many of their life processes.

D.
When cyanobacteria evolved, they carried out photosynthesis. Oxygen is needed to carry out photosynthesis.

Answer 2

@shifuyanli

Answer 3

what do you think?

Answer 4

any ideas?

Answer 5

@Sworewolf?

Answer 6

sorry i was afk.

Answer 7

@shifuyanli

Answer 8

i was afk

Answer 9

any ideas?

Answer 10

looking

Answer 11

i think B, C, D
@shifuyanli

Answer 12

@7thGrader