What is the primary function of the nervous system in the human body?

The primary function of the nervous system is to collect information for the body and indicate survival actions. This system is critical for processing sensory input from the environment, coordinating responses, and enabling communication between different parts of the body. The nervous system accomplishes this through complex networks of neurons that transmit signals rapidly, allowing for quick reflexes and decision-making essential for survival. It includes the central nervous system, which consists of the brain and spinal cord, as well as the peripheral nervous system, which connects the central system to the rest of the body.

The other options focus on different systems and functions within the body. The circulatory system is responsible for moving blood and delivering nutrients (the first option), while the immune system plays a crucial role in filtering out disease-causing organisms (the third option). The endocrine system is responsible for hormone production and secretion (the fourth option). Each of these systems plays vital roles in maintaining bodily functions, but none encapsulate the primary role of collecting information and directing survival actions as accurately as the nervous system does.