Which structure connects bone to bone?

The structure that connects bone to bone is a ligament. Ligaments are made of dense connective tissue and provide stability to joints by holding the bones together, allowing for a range of motion while preventing dislocations. They play a crucial role in supporting and stabilizing the skeletal system during movement and other activities.

In contrast, tendons connect muscles to bones, enabling movement when a muscle contracts. Cartilage is a flexible tissue that provides cushioning at joints and can also connect bone to bone in certain areas, such as the joints, but it does not have the same function as ligaments. Muscles, on the other hand, are responsible for movement and do not directly connect bones to one another. Thus, the unique role of ligaments in maintaining joint integrity and connecting bones makes them the correct answer.