Connective tissues like ligaments and tendons are made of collagen protein which provides strength and flexibility. While collagen is also found in bones, connective tissues do not contain calcium salts which is why they are not as hard as bone. Ligaments connect bones to bones at joints to form movable connections, while tendons connect muscles to bones to allow muscles to pull on bones and move parts of the body. Cartilage is a connective tissue found in many areas of the body like joints, ribs, spine, ears and nose that provides structure and acts as a cushion.