Question

Cyanobacteria were the first photosynthetic organisms. How were they responsible for allowing higher life forms to evolve?Select one of the options below as your answer:
A. They released oxygen, which mixed to form iron, and later ferrous oxide, in the air.
B. They released carbon dioxide, which evolving animals needed.
C. They released oxygen, which created the ozone layer, resulting in reduced mutation rate.

Answer 1

The answer is C.