Answer: A
Explanation:
"That's what evolution is all about: tiny changes in organisms of a species over a huge amount of time."
I think the best answer is D. It is thought that advances such as agriculture, literacy, and urbanization have not been accompanied by additional increases in brain size because the physiological cost of a bigger brain exceeds its benefit. The brain requires a lot of nutrients to function. Having a bigger brain would cost a lot rather than benefiting from it.
