The skull is made up of 30 different bones. Most people have 12 pairs of ribs. The spine discs allow you to twist and bend. It also protects your spinal cord. A disc is made of cushiony cartilage.
Marrow helps bodies and bones because it helps produce blood.
In the way it helps is making blood cells that take oxygen and help muscles move so your bones move. In the Nervous System there is the brain and the nerve cells. The spinal cord helps the brain send messages to your body, but is not one of the main organs. The nerve cells help to send messages , too. The brain is made up of 2 main parts, the Central Nervous System and the Peripheral System.