Final answer:
The nervous system coordinates balance, movement, and relaxation for a surfer, utilizing senses and muscle control. It also regulates the body's response to stress.
Step-by-step explanation:
The nervous system enables the surfer to balance, move, and relax through its coordination of various functions. When balancing, the central and peripheral divisions of the nervous system utilize the senses of balance, body position, and touch on the soles of the feet to maintain equilibrium. The nervous system controls the muscles involved in movement, allowing the surfer to stay upright and execute maneuvers. Additionally, the nervous system plays a role in relaxation by regulating the body's response to stress through the sympathetic and parasympathetic nervous systems.