Which system controls unconscious, involuntary body functions?

The autonomic nervous system is the correct answer because it is specifically responsible for regulating unconscious and involuntary body functions. This system controls essential physiological processes such as heart rate, digestion, respiratory rate, and blood pressure without requiring conscious thought or effort from the individual.

It is divided into two main branches: the sympathetic and parasympathetic nervous systems, which work together to maintain homeostasis and respond to stress. For example, during stressful situations, the sympathetic branch triggers the "fight or flight" response, while the parasympathetic branch helps the body relax and conserve energy afterward.

In contrast, the somatic nervous system manages voluntary movements and the control of skeletal muscles, requiring conscious effort to execute these actions. The cerebral cortex is involved in higher-order brain functions such as thinking and decision-making but does not directly control involuntary processes. The peripheral nervous system encompasses both the somatic and autonomic nervous systems, but it is the autonomic division that specifically governs involuntary control of bodily functions.