Anthropologists and biologists have generally reasoned that high concentrations of melanin arose in the skin of peoples in tropical areas because it protected them against skin cancer.
Anthropologists and biologists have generally reasoned that high concentrations of melanin arose in the skin of peoples in tropical areas because it protected them against skin cancer.
人类学家与生物学家通常是这麽推论的：热带族群的皮肤里，黑色素浓度很高，因为黑色素能保护他们不会得皮肤癌。