First off forensic anthropology is often used to distinguish race (and/or sex) simply from bone structure. DNA analysis (i.e. genetic markers) have also been used. So there certainly are biological and anthropological differences. As to subhumanity of them, idk, I wouldn't call a chihuahua "sub dog" though they are notably less intelligent than other breeds like border collies or australian shepherds. But certainly there are trends in racial populations that show significant (i.e. statistically significant) mental and physical differences. Most of these you have to go back >50 years to find though, because around the Civil Rights era all of that research was basically a non-starter for funding. In terms of intellect sub-Saharan Africans and their descendants rank bottom - to deny that is to deny hundreds (maybe thousands) of years of data on the topic, and to ignore public policy today that favors them specifically (if not explicitly) because of that well-established fact. There was a prominent biologist (and not James Watson; IIRC it's a woman) who spoke about censorship of research into the differences between races and now sexes was being critically suppressed. I can't find the article now; I read it about 2+ years ago.