Final answer:
Humans, specifically Homo sapiens, are classified in the family Hominidae because of several distinguishing characteristics.
Step-by-step explanation:
Humans, specifically Homo sapiens, are classified in the family Hominidae because of several distinguishing characteristics. In addition to being able to swing our arms in a circle and having flat, broad chests, humans share common features with other members of the family Hominidae, including the possession of a backbone, hair, and milk glands. The family Hominidae is part of the order Primates, which includes great apes and humans.