The greater amount of eumelanin in darker skin protects folate from being broken down by UV radiation and thus increases fitness among populations in high-intensity UV areas. ... However, it does not explain why there is variation in human skin color.
Mama mia thatsa spicy meataballa
A zero percent chance that the son will have hemophilia and a 100 percent chance that the son will be a carrier for hemophilia
Humans can will themselves to eat more, as we know that food comes easy to us.
Animals, on the other hand, top priority is survival, so they usually wouldn't think about eating more because it just "tastes good."