The ten major bones in the human body are: the cranium (skull), mandible (lower jaw), vertebral column (spine), sternum (breast bone), ribs, pelvic girdle (pelvis), femurs, patella (knee cap),...
I can provide one reason, but I am shaky on the other. Basically, the bone marrow (the foam stuff in your bone) creates red blood cells, which are vital for survival. Red blood cells transport oxygen...