What was the genetic variation of dark moths and how did it occur?

Natural Selection

Explanation:

A random genetic mutation gave rise to the dark colored moths. All types of living things have small differences between the individuals in the species. If one of those differences allows the individual to live longer, they will likely have more offspring. As that trait is passed on, the population starts to look more like a successful individual. Over time, the species changes.

the correct answer is b