Question

In a mouse population, some mice have thicker fur than others, but there are more mice with thinner fur. The climate in which these mice live has slowly gotten colder.

How will this change in the environment most likely affect the mouse population?

The adaptation of thinner fur will be selected over thicker fur, and the population will remain unchanged.
The adaptation of thicker fur will be selected over thinner fur, and the population will remain unchanged.
The adaptation of thinner fur will be selected over thicker fur, and the population will evolve.
The adaptation of thicker fur will be selected over thinner fur, and the population will evolve.

Answer 1

The adaptation of thicker fur will be selected over thinner fur, and the population will evolve.

Reason: As the climate gets colder, mice with thicker fur have higher survival/reproductive success, so alleles for thicker fur increase in frequency over generations — a change in the population (evolution).