Question

For photosynthetic organisms to evolve and become more abundant than chemosynthetic organisms, what variable must have changed in the environment of ancient Earth?

Answer 1

A- Oxygen must have become more abundant.
B- Nitrogen must have become more abundant in the atmosphere.
C- Endosymbiosis needed to occur between a smaller prokaryote and a larger prokaryote.
D- Carbon dioxide must have become more abundant.

Answer 2

http://en.wikipedia.org/wiki/Ecology read this it will help

Answer 3

@shrutipande9

Answer 4

@barreraA any idea?

Answer 5

hold on a sec ok

Answer 6

ok

Answer 7

its between A or C