What is the primary function of the nervous system?

The primary function of the nervous system is to control body functions and interact with the environment. This system is essential for coordinating voluntary and involuntary actions, processing sensory information, and facilitating communication between different parts of the body. The nervous system enables organisms to respond to stimuli from their surroundings and helps in maintaining homeostasis by regulating bodily functions. It comprises the central nervous system (brain and spinal cord) and the peripheral nervous system, which work together to relay messages between the body and the brain, ultimately allowing for complex behaviors and responses.

The other options, while important bodily functions, do not pertain specifically to the nervous system. Hormone production is primarily the role of the endocrine system, blood transport is managed by the circulatory system, and the delivery of nutrients to cells is facilitated by both the circulatory and digestive systems. Therefore, the choice that highlights the nervous system's role in function and interaction underscores its pivotal influence on overall bodily operations.