Final answer:
Primates are unique due to their arboreal heritage and distinct adaptations such as specialized limbs and sensory organs. They also exhibit complex behaviors and a tendency to live in social groups.
Step-by-step explanation:
Primates are unique due to several adaptations that have allowed them to thrive in different habitats and exhibit complex behaviors. One of the key features of primates is their arboreal heritage, which has led to adaptations such as a rotating shoulder joint, widely separated thumbs and big toes for gripping branches, and stereoscopic vision for depth perception. Additionally, primates have larger brains than many other mammals, longer lifespans, and tend to live in social groups. These characteristics contribute to their distinct evolutionary path.