Explain How have people become pegged, as it were, to their ethnic group?

*How did people become identified, historically, as heterosexual or homosexual (note that these specific distinctions were unknown until the latter part of the nineteenth century)? *How have people become pegged, as it were, to their ethnic group? (Note that St. Augustine in the fourth century CE may have been black, that is, Afro-Roman; it would not have occurred to the Romans to mention his ethnicity.) Speculate as to why these distinctions are so important to Americans. What do they say about American culture?