Actually, you've exposed your own ignorance on a pretty basic topic. Kinda sad really. Disappointing too? Let give it one last shot. Is the following true?
Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics (inherited from one's biological parents), the exposure to the sun, or both. Differences across populations evolved through natural selection, because of differences in environment, and regulate the biochemical effects of ultraviolet radiation penetrating the skin.