A population of deer mice with light-colored coats lives in Sand Hills, Nebraska. The ground in Sand Hills is light colored where glaciers have deposited sand on top of dark soil. In contrast, areas outside Sand Hills have dark soil and dark-coated mice. Scientists found that the light-colored mice have a genetic mutation for the light coat color. What does this mean?
A. Mice are able to change their coat color at will.
B. Light sand caused the coats of the mice to mutate to a lighter color.
C. Mice learned how to change their coat to a lighter color.
D. Light-colored mice were selected for on light-colored sand.