In northern Canada a population of rabbits was predominantly white in color. The allele for white color is recessive while the allele for gray color is dominant. Over the last several decades, the average annual temperature of this area has increased and the long-term deposits of ice and snow have become scarce. This is an example of directional selection which tends to
A) decrease genetic diversity.
B) increase the frequency of a previously scarce allele.
C) decrease the frequency of a previously scarce allele.
D) increase the frequency of two previously rare alleles.

Directional selection tends to evolve towards one specific trait. In this example, white rabbits no longer have a competitive advantage because of disappearing snow. This means they are more easily spotted by predators, resulting in reduced fitness and less chance they will live to reproductive age and pass their recessive white alleles on.

Natural selection will favor the gray colour allele, increasing the frequency oft this previously rare allele.