Yellow bone marrow is made up of a large percentage of fat. It is found in the hollow, long bones of the human body and is used to store energy in the form of lipids.
There are two types of bone marrow in the body: yellow and red. The red marrow contains blood stem cells, white blood cells or platelets. Red bone marrow produces red and white blood cells, which it uses to form hemoglobin from the marrow's store of iron. The red bone marrow in the body gradually drops off after a person reaches puberty and is replaced with yellow bone marrow.