Question

john and pat are identical twins with identical dna. john works in a movie theater, and pat works as a lifeguard. they have very different skin pigmentation. which is the best explanation of the difference? skin color, a polygenic trait, is also determined by environmental factors. skin color, a polygenic trait, is also determined by the sex of the individual. skin color, a trait that demonstrates incomplete dominance, is also determined by environmental factors. skin color, a trait that demonstrates incomplete dominance, is also determined by the sex of the individual.

Explanation:

Identical twins have the same DNA. Skin color is a polygenic trait influenced by multiple genes. Since their genetic makeup is identical, the difference in their skin - pigmentation is most likely due to environmental factors. John works in a movie theater (less sun exposure) and Pat works as a lifeguard (more sun exposure). Sun exposure is an environmental factor that can affect skin pigmentation.

Answer:

Skin color, a polygenic trait, is also determined by environmental factors.