The trouble is PC has inserted itself into the undeniable fact that all mammals evolve to suit local circumstances. We were all black, when in Africa. When we w

The trouble is PC has inserted itself into the undeniable fact that all mammals evolve to suit local circumstances. We were all black, when in Africa. When we went north, the lesser sunlight caused shortages of vitamin D (which humans can not make from their food - they use sunlight to make it) This cases many problems. https://www.google.ca/search?q=shortages+of+vitamin+D&oq=shortages+of+vitamin+D&aqs=chrome..69i57&sourceid=chrome&ie=UTF-8 https://www.google.ca/search?q=shortages+of+vitamin+D&oq=sho... African sun also cases skin cancer, so the melanin cells evolved to let the Vitamin D wavelengths through, but attenuate the cancer causing rays. Curly hair also acts as insulation to keep the brain cool. As we moved North we lost those. Hair got straighter, and skin paler. When we moved back South we evolved darker skin, as in India and Asia. But the hair stayed straight. Apart from that, all the races are more or less the same.