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

B.
Oxygen is a product of photosynthesis. When cyanobacteria evolved, they began to carry out photosynthesis.

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.
Oxygen is needed to carry out photosynthesis. When cyanobacteria evolved, they began to carry out photosynthesis.
 
 B.
Oxygen is a product of photosynthesis. When cyanobacteria evolved, they began to carry out photosynthesis.

gelow · Answer

C.
Adding oxygen to earth's atmosphere allowed for the development of prokaryotic organisms, which need oxygen to carry out many of their life processes.
 
 D.
Adding oxygen to earth's atmosphere allowed for the development of eukaryotic organisms, which need oxygen to carry out many of their life processes.

anonymous · Answer

I would say B, but I'm not sure. and if you want a good answer I suggest posting this in the `Earth Science`

gelow · Answer

thx