Bone marrow is the flexible, spongy tissue found in the hollow center of most bones . Often described as a "factory," its primary job is to create nearly all of your body's blood cells. It accounts for about 4% to 5% of total body weight, which is roughly 6 pounds in an average adult. Types of Bone Marrow
The body contains two main types of marrow, categorized by their color and function: Bone Marrow: What it is & Why it is Important