Answer
b.
Work Step by Step
Option a. is incorrect. Body hair is a characteristic of all mammals, not only of primates.
Option c. is incorrect. A notochord is a characteristic of all chordates, not just primates.
Option d. is incorrect. The ability to regulate internal body temperature is a characteristic of all endotherms, which includes the mammals and birds, not just primates.
Option b. is correct. Rotation of the shoulder joint allows primates to climb trees and swing almost effortlessly from branch to branch.
