Question

How would you justify that Australopithecus was a human ancestor? 

Answer 1

Australopithecus averaged about 120 cm tall, and the cranial capacity ranged from 450-600 cm³. It had a low forehead, protruding face, lack of chin and low brain capacity. Teeth resembled man because the dental arc was a smoothly rounded parabola, and a simian gap was absent which justifies a human ancestor.