Which system is primarily responsible for locomotion in humans?

The musculoskeletal system is the primary system responsible for locomotion in humans because it consists of bones, muscles, joints, and associated connective tissues that work together to facilitate movement. Muscles contract to create the forces necessary for movement, while bones act as levers that these muscles pull on during activities such as walking, running, and jumping. The joints between bones provide the flexibility and range of motion needed to perform a variety of movements.

In contrast, while the nervous system plays a critical role in coordinating movement by sending signals to muscles, it does not directly produce locomotion. The circulatory and respiratory systems support bodily functions such as supplying oxygen and nutrients and removing waste products, but they do not directly contribute to the physical act of movement. Thus, it is the musculoskeletal system that is fundamentally responsible for enabling locomotion in humans.