Answer:
a. The number of chromosomes in a sperm cell is half of the number of chromosomes in the skin of a dog, so there are 74/2 = <<74/2=37>>37 chromosomes in each sperm cell.
b. The number of chromosomes in a heart cell is the same as the number of chromosomes in the skin of a dog, so there are 74 chromosomes in each heart cell.
c. The term "somatic cell" refers to any cell in the body that is not a gamete, so the number of chromosomes in a somatic cell is the same as the number of chromosomes in the skin of a dog, which is 74.
d. Gametes are reproductive cells that are involved in sexual reproduction, and they have half the number of chromosomes of other cells in the body. In the case of a dog, there are 74 chromosomes in the skin, so each gamete would have 74/2 = <<74/2=37>>37 chromosomes. This is true for both sperm cells and eggs.