D. It's harder body parts. A lot of fossils are of the skull, therefore that would lead one to think that it would be harder<span />
I'm not sure but but i think the answer will be:
A. additive genetic variance times the selection differential.
<span>The behavior that is not a result of seasonal changes is : C. circadian rhythm
Cicadian rhythm refer to the Physiological cycle that's experienced by living organisms within a day, This cycle is not a reasolg of seasonal change because the factor that influence it the most is time period within 24hours, and the time process usually the same no matter what season they are in</span>
I believe the answer is B.