Final answer:
The muscles in the esophagus contract to move food to the stomach due to the interaction of the digestive system and the muscular system, controlled by the autonomic nervous system.
Step-by-step explanation:
The systems that are interacting when the muscles in the esophagus contract to move food to the stomach are the digestive system and the muscular system.
The muscles in the esophagus are responsible for peristalsis, which is the wave-like contractions that push food down the esophagus.
This movement is controlled by the autonomic nervous system, which is part of the nervous system.
Learn more about interaction of systems in digestion