What role do ligaments serve in the skeletal system?

Ligaments serve a critical role in the skeletal system by connecting bone to bone or cartilage. This connection is essential for maintaining the stability and integrity of joints, as ligaments help to hold bones together and prevent excessive movements that could lead to injury. Their function is particularly important in areas such as the knees, elbows, and shoulders, where joint stability is necessary during movement. By forming connections between bones, ligaments help to ensure that the skeletal framework functions properly, allowing for coordinated movement without dislocation or injury.

The other options represent functions associated with different components of the musculoskeletal system. For instance, muscles connect to bones through tendons, which facilitate movement by contracting and pulling on the bone. Additionally, while the skeletal system does provide some level of protection to internal organs, such as the rib cage protecting the heart and lungs, this is not the primary role of ligaments. Thus, the correct answer highlights the specific function of ligaments in connecting bones and cartilage, which is essential for joint stability.