B. Muscular system
The muscular system is responsible for contracting and causing movement in the body. It is made up of muscles, which are specialized tissues capable of contracting and relaxing. When a muscle contracts, it generates a force that allows movement to occur. This includes movements of the limbs, facial expressions, posture adjustments, and internal processes such as digestion.
The muscular system works in conjunction with the nervous system, which sends signals to the muscles to initiate and coordinate movement. The nervous system relays messages from the brain to the muscles, instructing them to contract or relax as needed. This communication between the nervous system and the muscular system allows for precise control and coordination of movements.
While other body systems, such as the respiratory system, cardiovascular system, and nervous system, contribute to overall bodily functions, it is the muscular system that directly contracts to produce movement.