There should not be any changes in the gene pool.
In Hardy-Weinberg equilibrium, the gene pool should have a constant rate. The equilibrium can be achieved if there is no factor that favors one gene more than the others. Since the genes have the equal chance to survive and mating, the ratio of the gene pool should not change dramatically.
Biochemical- apart of the second defense system
Answer: Hairlessness and Glands
explanation:Another notable similarity between the two groups is minimal hair. Both hippos and whales possess barely any hair on their bodies. They do not have sweat glands, either. These are both characteristics that can assist them in their aquatic lifestyles.
C is most likely your answer (my bad if I am wrong)