This is actually a really easy distinction to make, and the fact people get so autistic about asking shows that they know nothing and just want to undermine/stir shit in an attempt to help turn the planet into a giant zoo for shit-flinging apes.
The only featherless bipeds which warrant the status of human being currently alive are the product of three different specific ancient populations, all mixed together in varying degrees. Adjecent/"borderline" populations that don't warrant being called human beings and which should be converted into fertiliser have mixture from alien ancestral groups not belonging to those three. Realistically only about 700 million humans actually exist on Earth and there are 7+ billion disgusting shitting retarded gorillas that need to be thrown into an oven.