Final answer:
The autonomic nervous system controls involuntary functions such as heart rate, blood pressure, digestion, and sweating.
Step-by-step explanation:
The autonomic nervous system (ANS) controls involuntary functions in the body, such as heart rate, blood pressure, digestion, and sweating. It is responsible for maintaining homeostasis, which is the regulation of the internal environment. The ANS is divided into two main branches: the sympathetic and parasympathetic nervous systems. The sympathetic system prepares the body for stress-related activities, while the parasympathetic system returns the body to routine, day-to-day operations.