What's the Name of That Book??? discussion

I read a book in the mid-80s (it may have been older) about a group of teens that found out that they were the last of their respective races. I seem to recall that were was at least one White, one Black, and one Asian. I don’t remember if there were any others. They were living in towns of others of their “race” but came to find out that underneath their façade they were all a uniform brown color. IIRC, after finding this out, they felt like they were living in a zoo. Somehow, they all manage to come together and get on a spaceship where they begin to find out about the history of Earth. When they try to go to Earth, they discover they are already there.

Race Against Time by Piers Anthony?

Yup, I second that.

I think that's it. Thanks all!!