Final answer:
The autonomic nervous system controls involuntary functions such as heart rate, blood flow, and digestion.
Step-by-step explanation:
The autonomic nervous system controls involuntary functions such as heart rate, blood flow, and digestion. It sends messages between parts of the nervous system and other organ systems. For example, you don't have to consciously tell your heart to beat or actively control your digestion, as the autonomic nervous system takes care of these functions automatically.