"Race" is a term that is falling out of use. It's better to use the term "population". Race is actually a social construct. For example, there was a time before a wave of eastern european immigrants and italians were not considered "white". After they moved into the suburbs and miscegenated (breeding between "races") italians, in the United States, became "white". Race is something that is constantly being formed, I suggest reading "Racial Transformation in the United States" if you are a college level student. It talks about different paradigms (what ideas are used to explore a subject) of race, we have moved from a biolgical paradigm into a more ethnic paradigm. Race is not something defined across borders, Obama isn't "black" in Brazil.