Ethnic problems in South American countries

A large part of South America is indeed mixed-race, which includes whites, blacks and Indians, that is, yellow people.

But in the beginning, South America was a colony of European countries, and many European whites disdained to marry the locals and kept their own white characteristics. Your two classmates either belong to this kind of white family, have no mixed blood or have mixed blood in their ancestors, but they are not obvious after many generations, or they have just immigrated from Europe to South America recently, maybe they are grandparents or something.