The first lower premolar of chimpanzees has ________, the first lower premolar of humans has ________, and Australopithecus afarensis had ________.
A) two equal cusps; no cusps; a small and a large cusp
B) one cusp; no cusps; two equal cusps
C) one cusp; two cusps; no cusp
D) one cusp; two cusps; a small and a large cusp

Question

Quizplus · Accepted Answer

The first lower premolar of chimpanzees has one cusp, indicative of their specialized diet and chewing patterns. Humans, having evolved different dietary needs and oral mechanics, have two cusps on their first lower premolar. Australopithecus afarensis, an early human ancestor, had a first lower premolar with a small and a large cusp, showing a transitional dental morphology between modern humans and their ape-like ancestors.

The First Lower Premolar of Chimpanzees Has ________, the First