13. In a long bone, such as the femur in the leg, the center of the bone contains which substance, responsible
for producing blood cells?
O A. Marrow
O B. Ligaments
O C. Synovial fluid
O D. Plasma

A. Marrow

Explanation:

Marrow is usually found in some bones of the body. The marrow contains fatty stem cells. This stem cells acts as a rich site for blood production in the body.

This is the main reason why marrow transplant technology was discovered to help patients with serious issues regarding anaemia.