Those weren't "races" (whatever that means) but subspecies, or ~species that were close enough to breed. As with several species of cats that can crossbreed.[0]

Those weren't "races" (whatever that means) but subspecies, or ~species that were close enough to breed. As with several species of cats that can crossbreed.[0] Modern humans are all Homo sapiens. All other Homo species merged, and were killed, thousands of years ago. I don't think that any surviving Homo groups are distinct enough to be called subspecies. And the concept of "race" has been abused so thoroughly, as the justification for colonialism and slavery, that it's out of favor. But the fact remains that reduced interbreeding, through geographic and/or social constraints, does produce distinguishable populations. We could call them breeds, I suppose, as with dogs and cats. And if it went on for long enough, on the order of say 10^5-10^6 years, new species could emerge. 0) https://www.thesprucepets.com/hybrid-cat-breeds-4176576 https://www.thesprucepets.com/hybrid-cat-breeds-4176576