What is the primary function of bone marrow?

The primary function of bone marrow is to produce blood cells. This vital process occurs in the red bone marrow, which is responsible for generating red blood cells, white blood cells, and platelets. Red blood cells are essential for transporting oxygen throughout the body, white blood cells play a crucial role in the immune system by fighting off infections, and platelets are necessary for blood clotting.

While bone marrow does have a supportive role in the body that relates to the skeletal system, its central importance lies in hematopoiesis—the production of blood cells. Storing energy, absorbing nutrients, or providing structural support are functions carried out by other systems and tissues in the body, but they do not pertain to the primary role of bone marrow. Thus, the focus on blood cell production highlights why this choice is correct, emphasizing its critical function in maintaining overall health and vitality.