<unk>  (or medulla ossea) is the soft tissue found in the hollow interior of<unk> s. In adults,<unk>  in large<unk> s produces new blood cells. It constitutes 4% of total body weight, i.e. approximately 2.6 kg (5.7 lbs.) in adults.
Bone marrow
Spleen
Thymus
Lymphatic tissues
Nephron
Heart
Brain
Hematopoietic stem cell