What is one of the primary functions of the musculoskeletal system?

The primary function of the musculoskeletal system is to provide support and protection for the body, particularly for internal organs. The bones of the skeletal system form a rigid framework that safeguards vital organs such as the heart, lungs, and brain. In addition to protection, the musculoskeletal system also plays a vital role in movement and maintaining posture through the interaction of bones, muscles, and joints.

The other options relate to different bodily systems: lymph production is a function of the lymphatic system; blood circulation is handled by the cardiovascular system; and hormone regulation is primarily managed by the endocrine system. Each of these systems contributes to the overall functioning of the body but does not reflect the main purpose of the musculoskeletal system, which centers around protection and structural support.