Brown
Brown in science and nature
A dark brown iris is most common in East Asia, Southeast Asia, and South Asia. A light brown iris is most common in North Africa, Eastern Europe, the Americas and West Asia. Brown is the second most common color of human hair, after black. It is caused by higher levels of the natural dark pigment eumelanin, and lower levels of the pale pigment pheomelanin. Brown eumelanin is more common among Europeans, while black eumelanin is more often found in the hair on non-Europeans. A small amount of black eumelanin, in the absence of other pigments, results in grey hair. A small amount of brown eumelanin in the absence of other pigments results in blond hair.
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