Which best describes the lower body structures of humans and chimpanzees?
a. the big toes of humans and chimpanzees are enlarged.
b. the human foot has two arches, but the chimpanzee foot only has one.
c. human knees are very mobile, but chimpanzee knees are stabilized by tendons.
d. the blades of the human pelvis are not rotated inward like those of the chimpanzee

The answer is (b.) The human foot has two arches, but the chimpanzee foot only has one.

The difference in the lower part of the body structure between a human and a chimpanzee is the foot. Chimpanzee only has one arch compare to humans who have two. The arches of the feet refer to the formation of tarsal and metatarsal bones. It allows the the foot to support the weight of the body.