B. 245 million
from the end of Carboniferous Period to the beginning of the Triassic period
In all honesty, I believe it is. Here's why...
Prokaryotic cells are important to ALL life on earth. They play a critical role in the recycling of nutrients by decomposing dead organisms and allowing their nutrients to be re-used. They are also important for many metabolic processes. So in the end they are important.
<em>~Noodles~</em>
The answer is A) they provide a source of energy.
C ITS C I TOOK IT I took the test