African American fingernail

Mike was reading a book about slavery to the kids, and they were talking about different races. Afterwards, Noah asked me, "Am I black or white or what?"  Sarah said, "We're brown, Noah."  I told them they're not black or white, but they're Asian.  Sarah looked at the bruise on her fingernail and said, "Everything on me is Asian except my fingernail.  It's black."