Section: Science

12)

The polar bear's dense fur and an exceptionally thick layer of fat under its skin protect it against the freezing temperatures of the habitat.

How is natural selection in the evolution of a thick coat of fur in polar bears best explained?

Polar bears with thicker fur only mated with other polar bears with thick fur.
Polar bears with thinner coats of fur were killed off by polar bears with thick coats of fur.
Polar bears with thinner fur head south for the winter
Polar bears with thinner fur did not survive because they were not well suited to the environment.
Polar bears fur grew thicker because of genetic mutations of the animals.