Can someone give me 2 example of a single allele trait in animals?

Which statements describe incomplete dominance? traits are usually dominant. traits are neither dominant nor recessive. offspring exhibit an intermediate form of alleles from the parents. both alleles, one from each parent, are expressed in offspring. incomplete dominance involves the interaction of two alleles.

Alaska and northern canada have a diet rich in vitamin d and their skin color is darker than predicted on the basis of iv intensity at their latitude. explain the observation:

Melting glaciers is a serious threat to the environment what is the possible consequence of melting glaciers on polar bears?