Because the white (Caucasian) race is not a biological category such as the human ( sapiens) race, they?

cannot possibly go "extinct", no? They can't only "merge" with other humans like how brown-haired people can carry blond hair ( though not showing ) and brown-eyed people can carry blue eyes ( though not showing )? Because the white race is not a biological category, as in the case of the Japanese race, both the white race and the Japanese race cannot go "extinct", no? Extinction is only applicable to biological categories such as the human race, the mammal race?