Bones form the structure of your body. They allow you to stand, sit run play and twist yourself up like a pretzel. Without them you'd be nothing but a big soft blob. Some bones like your rib cage and pelvis protect your internal organs. Muscles attached to your bones allow you to move. Bones manufacture blood cells and store fat and calcium a mineral that keeps bones strong. There are two kinds of bone tissue compact bone and spongy bone. Compact bone tissue is rock hard because it's made of the same minerals found rocks calcium phosphates and magnesium. The twenty nine bones of your skull form a strong protective shell around your brain eyes and inner ear. The upper jaw which is called maxilla it attached to the rest of the skull and can't move. The lower jaw which called the mandible. The human body is strengthened supported and held  up by parts which we cannot see bones. All the bones together make up the skeleton. Most people have 206 bones. 

A baby's skeleton has 300 or more bones however, some of these fuse join together as the baby grows. In addition, most women and girls have smaller and lighter skeletons than men and boys. However in women and girls the pelvis is much wider than in men and boys. For the openinghas to wide enough for a baby to pass throughwhen it is born.