Australopiths Show a Trend Toward Improved Upright Walking, Smaller Teeth

Australopiths show a trend toward improved upright walking, smaller teeth, and greater hand dexterity. Like other early hominins, they retained a ____.

A) vertically split upper lip
B) skull that opens to the spinal cord at the rear
C) modern human-sized brain
D) chimpanzee-sized brain
E) prehensile tail