Final answer:
a) Proximal. The position nearest to the center of reference points or the body is termed as proximal. It implies a location closer to the point of attachment or trunk of the body, as in the brachium being proximal to the antebrachium.
Step-by-step explanation:
The term that refers to a position nearest to the center of reference points or the body is proximal. This anatomical term is used to describe locations on the body in relation to other reference points. For example, the brachium (upper arm) is proximal to the antebrachium (forearm) because it is closer to the main mass of the body, especially when speaking about limbs or structures that are attached to the trunk. Proximal contrasts with distal, which describes a position farther from the point of attachment or trunk, such as how the crus (lower leg) is distal to the femur (thigh bone).
In addition to proximal and distal, other directional terms include medial, which refers to the middle or direction toward the middle of the body as seen with the hallux (big toe), and lateral, which describes the side or direction toward the side of the body, exemplified by the thumb (pollex) being lateral to the digits (other fingers).