What is the main feature of spongy bone?

The main feature of spongy bone is the presence of red marrow, which plays a crucial role in hematopoiesis, the process of blood cell production. Spongy bone, also known as cancellous bone, is characterized by a porous, lattice-like structure, allowing it to be lighter and provide structural support while also serving as a site for the production of blood cells.

Red marrow is found within the spaces of spongy bone, particularly in areas such as the ends of long bones, pelvis, ribs, and vertebrae. This is where new blood cells are generated, including red blood cells, white blood cells, and platelets. Thus, the association of spongy bone with red marrow is fundamental to its function in the body.

In contrast, the other options don't encapsulate this key characteristic of spongy bone. Compact bone, while present in the overall structure of bones, is not a defining feature of spongy bone. Yellow marrow, which is primarily composed of adipose tissue, is primarily located in the cavities of long bones and does not reflect the hematopoietic function that is associated with red marrow. Dense fibers are more characteristic of the composition of connective tissue but do not specifically identify or highlight