"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
Bone marrow makes up 4% of a human body mass. It produces red blood cells which carry oxygen all over the body. Marrow is also produces lymphocytes, key components of the lymphatic system, which support the body's immune system.