In order for biological evolution to occur, the environment would have to change drastically.

This is true because evolution occurs when organisms have to adapt to changes in environment. When we have changes in environment every organism will have to adapt to overcome their possible deficiency due to the new change. Those who do not adapt wil die off, while those who will addapt accordingly will prosper in the new environment as well. 

Ithink that b is correct but just in case wait to see if someone else answers

Ithink a saturated phospholipid