The Siamese cat breed has a light colored body and dark colored head, tail, and feet, all of which are called points. The Burmese cat breed has a dark colored body and points that are almost the same color as the body. Crossing Siamese with Burmese can produce the Tonkinese cat breed, which has coat and point color that is intermediate to the Siamese and Burmese parents.

In all three breeds, a temperature sensitive enzyme is responsible for the dark coloration of the points. However, it is active only at the extremes of the body where it is coolest. Select the statements that are true regarding the evidence of incomplete dominance and incomplete penetrance in these breeds.

a. Intermediate coat color in Tonkinese demonstrates incomplete dominance.
b. Development of points in Tonkinese demonstrates incomplete penetrance.
c. Light coat color in Siamese demonstrates incomplete penetrance.
d. Darker color at the extremes of the body in Tonkinese demonstrates incomplete dominance.

Because the Tonkinese breed has a coat that is intermediate to the coat color of the Siamese and Burmese, we can say that this demonstrates incomplete dominance which means that the dominant allele does not have the ability to completely mute the recessive allele in the phenotype.

This is also true because of the development points on the coat of the Tonkinese breed.

So the correct answer is A and B.

I hope this answer helps.