Africa's a continent. Europe is a continent and so is Asia. American racial descriptors don't really make any sense, which is why these questions get asked every other day.
Indians and East Asians are all considered Asians.
Most people don't realize that "Black" is a slur that describes the people that came to this country through slavery, which is why Europeans will often say that Ethiopians are black, but they aren't Black. In the same way African Americans came from Africa but aren't considered truly "African" by most people.
Europeans are white. White people can have ancestry from non-white people but are still considered white if there non-white ancestry isn't obvious when looking at them. Most white people are Caucasian, a term that describes the racial differences in skull shape. But Indians who in many cases are darker than Black Americans and can be darker than many Africans, are Caucasian. Ethiopians are black, but they are also Caucasian. Black Americans are Black but they are nee-groid.
Genetically speaking, there are no "races". Race is a social, economic, political and cultural reality but only fifteen percent of our DNA accounts for racial differences. What you see when you look at distinctive groups of people are varying degrees of genetic frequencies in different "ethnic" groups.
Moreover the thing to remember is that it's a single race of people that decide the criteria for which everyone is assigned a race, so there are political reasons for why a person from Egypt for example with kinky hair and dark skin will be considered Arab, as opposed to Black in this country...