Which system is primarily responsible for the reflex arc in the body?

The correct answer is the Peripheral Nervous System, as it plays a crucial role in the reflex arc. The reflex arc is a neural pathway that controls a reflex action. It starts with a sensory neuron that detects a stimulus, such as touching a hot object. This sensory neuron sends signals to the spinal cord, where the information is processed.

In the reflex arc, the central nervous system, which includes the brain and spinal cord, integrates the information but the execution of the reflex response relies heavily on the peripheral nervous system. Specifically, once the spinal cord receives the signal, it transmits an immediate response through motor neurons that are part of the peripheral nervous system. These motor neurons carry signals to the muscles, causing them to contract and produce a quick response without the need for the brain to be involved in that initial decision-making stage.

This system allows for fast responses to stimuli, essential for protecting the body from harm. Meanwhile, the central nervous system serves more as the processing center rather than the primary operative part in the reflex arc's immediate function, which emphasizes the importance of the peripheral nervous system in this context. The endocrine and immune systems are not involved in the reflex arc process, as they're responsible for hormonal responses and immune responses, respectively,