Which of the following best describes a long bone?

A long bone is characterized by its elongated shape and consists of a shaft, called the diaphysis, and two ends, known as the epiphyses. The structure of long bones includes a hard, dense outer layer, which provides strength and support, while the interior often has a spongy bone structure that contains marrow. This design allows for the efficient distribution of weight and the ability to withstand various forces, making long bones essential for movement and stability in the skeletal system.

In contrast, the other descriptions do not accurately represent the structure or function of long bones. Small, fragile bones reflect a different category of bone, while short and dense bones refer to those that are typically more compact, such as those found in the wrist or ankle. Round bones, such as sesamoid bones, are not elongated, making them distinct from long bones. Understanding the anatomy and classifications of bones is crucial for comprehending their roles in the body.