Acne is to excessive secretion of oil
Surprisingly chocolate actually contains a fair amount of iron. Red meats are known to contain iron, one thing in particular is blood (yes that is sometimes eaten, and it contains a lot of iron). Such organs of animals that are high in iron include the spleen and or marrow.
If you wish to go vegetarian red veggies tend to be high in iron, one in particular are beets (yes, i know, they aren't red until processed)
Answer: Adaptation
species adapt to their environment
It does not include plant sources.