What is the primary purpose of the nervous system?

The primary purpose of the nervous system is to transmit signals and coordinate responses throughout the body. This complex system is responsible for detecting changes in the environment, processing information, and then responding to those stimuli by controlling various bodily functions. The nervous system allows for communication between different parts of the body and integrates sensory information, enabling the organism to react appropriately to external and internal conditions.

For instance, when a person touches something hot, sensory receptors in the skin send signals through the nervous system to the brain, where the information is processed. The brain then sends signals back to muscles to move the hand away quickly, demonstrating the nervous system's role in coordinating rapid responses to stimuli.

Other options, while important bodily functions, do not encapsulate the primary role of the nervous system. Digestion is managed primarily by the digestive system, hormones are circulated by the endocrine system, and protection against pathogens is primarily the function of the immune system. Thus, the coordination of signals and responses is uniquely the domain of the nervous system.