After you swallow the first bite of your food, your stomach becomes active. polypeptides in the ingested food stimulate the stomach to release acid and enzymes, which creates more polypeptides. this greater concentration of polypeptides stimulates the stomach to release even more acid and enzymes, which continues until the contents of the stomach pass into the next digestive chamber. this phenomenon is best explained by

The right answer is positive feedback system.

Feedback refers to the feedback of a system to the modification of a parameter. The feedback mechanism is very often used in biology, but it is also used in cybernetics, finance, economics, and physics in a broad sense.

If the response of the system amplifies the phenomenon, then we will speak of positive feedback. If it attenuates it, we will speak in reverse of negative feedback.