Which is part of the theory of evolution by natural selection? A. All animals in a population are able to reproduce.
B. Animals have no variation among themselves.
C. Adaptations cannot be passed along to later generations.
D. Small changes add up over many generations.

D. Small changes add up over many generations.

Explanation:

It's not A because not all animals in a population can always reproduce. Some may be infertile.

It's not B because genetic variety is something that occurs naturally. Because of genetic variety, random mutations can occur (these mutations later become adaptations).

It's not C because adaptations can be passed down to later generations. These adaptations can lead to natural selection which eventually leads to evolution.

answer; i believe the correct answer to the above question is ( friction)