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?

Answer 1

Pat has likely been in the sun longer than John, since she/he works outside. Since she is outside longer, her/his skin has learned to adapt to it by producing more melanin to protect her/him. John doesn't go outside as much so his skin doesn't need to adapt to sun rays.

Answer 2

The answer is:

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

Hope it helps!