Final answer:
The correct description of a long bone is that it consists of a diaphysis (shaft) and an epiphysis at each end, with the diaphysis featuring compact bone and the epiphyses containing spongy bone and covered with articular cartilage where joints are formed.
Step-by-step explanation:
The statement that accurately describes the exterior structures of a long bone is: A) A long bone consists of a diaphysis (shaft) and an epiphysis at each end.
The diaphysis is the tubular shaft that runs the length of the bone, and its walls are composed of dense, hard compact bone. Inside the diaphysis is the medullary cavity, which is filled with yellow marrow. The epiphysis (plural: epiphyses) refers to the wider sections at each end of a long bone, which are filled with spongy bone and red marrow. The outer surface of the bone is covered with a fibrous membrane called the periosteum, except for the areas covered with articular cartilage, which is found at the ends of the epiphyses where the bone forms joints.