A member of the primate family Hominidae distinguished by bipedal posture and, in more recently evolved species, a large brain.

• A. Ethnology
• B. Primate
• C. Adaptation
• D. Hominin

Answer: (D)

Identifying the human lineage within the great apes hinges on two defining traits: bipedal locomotion and brain enlargement in later members. Hominidae is the family that includes all great apes and humans, but the term that specifically names humans and their fossil ancestors after diverging from chimpanzees is hominin. Hominins are characterized by walking upright and, in more recent species, having a significantly larger brain. The other terms don’t refer to a lineage: ethnology is about cultural variation, primate is a broad category, and adaptation is a general process. So the description points to hominin.