All the things that differentiate race are genetic, sure, but which things are used to categorize people into race is socially constructed. Why do people base r

All the things that differentiate race are genetic, sure, but which things are used to categorize people into race is socially constructed. Why do people base racial categories on skin color but not, say, finger length or whether you can wiggle your ears? Biology can't tell you that. https://en.wikipedia.org/wiki/Race_(human_categorization) https://en.wikipedia.org/wiki/Race_(human_categorization)