The skeleton has several key functions: 1) Movement - The bones and joints work with muscles to enable movement like walking, bending, and rotating. 2) Protection - The hard nature of bones protects delicate organs like the brain, heart, and lungs. 3) Support - Bones provide the framework that supports the body and allows it to stand upright. 4) Blood cell production - Bone marrow inside bones produces red and white blood cells. 5) Mineral storage - Bones act as a reservoir for minerals like calcium and phosphorus.