Well do you go by the American definition of race, do you go by the Brazilian color scale, or something else? In the US you are considered black if you have at

Well do you go by the American definition of race, do you go by the Brazilian color scale, or something else? In the US you are considered black if you have at least one black ancestor. Why not the other way around? Race in terms of biological definition is not consistent or coherent. There is also a lot of genetic variation within socially classified races.