The answer is E, tendons. The other options are all bones. Tendons are tough, fibrous cords that attach muscles to bones. They allow muscles to pull on bones, which is how we move our bodies.
Skull: The skull is a bony structure that protects the brain. It is made up of 22 bones, including the frontal bone, parietal bones, temporal bones, occipital bone, sphenoid bone, and ethmoid bone.
Spine: The spine is a column of bones that runs down the back. It is made up of 24 bones, including 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae, and 1 coccygeal vertebra.
Ribs: The ribs are 12 pairs of bones that form the rib cage. They protect the lungs and heart.
Femur: The femur is the longest and strongest bone in the body. It is the thigh bone.