Question

the population of mice is in an environment with many black rocks. mice with brown fur are less likely to survive and reproduce than mice with black fur. after many generations, most of the mice in the population have black fur. a sandstorm covers most of the populations environment with brown sand. mice with brown fur are more likely to survive and reproduce than mice with black fur. after many generations, most of the mice in the population have brown fur.

Explanation:

This scenario describes natural selection (a key concept in Biology). Initially, black - furred mice are favored in a black - rock environment. After a sandstorm changes the environment to brown sand, brown - furred mice become favored, leading to a change in the population's fur color over generations. This is evolution by natural selection, which is studied in Biology.

Answer:

The subfield is Biology. The process shown is natural selection (evolution) where environmental changes drive changes in the mouse population's fur color over generations, a core concept in Biology.