So, you have sex, beer, race, in that order. Of course, students think a lot about sports, too, particularly when Penn's teams in football or basketball are winning or when the Eagles, the Flyers, the '76s, or the Phillies are contenders. So, maybe, sports are in a tie with race for students' attention. Non-whites are particularly obsessed with race. And myths abound on the subject.
Race is another way of saying sub-species.
But let's turn to humans, which everybody is interested in. But there does seem to be agreement that there are some. In the last case, the geography is not obvious. Examples of this are Mexico, Peru, Chile, many countries in Latin America, but particularly Mexico, which is where most of this country's Latin American immigrants come from. The U.S. Bureau of the Census agrees with me.