Answer:
The entry of food into the stomach.
Explanation:
Gastric secretion is triggered by the act of eating which is called as reflex phase and the entry of food into the stomach called a gastric phase. The entry of the food particles into the small intestine also helps to control the secretion of gastric called an intestinal phase.
The secreted fluid in the small intestine contains some ions, acids, etc such as pepsinogen, intrinsic factor, bicarbonate, hydrochloric acid, and mucus. The reflex phase or cephalic phase helps to stimulate parasympathetic neurons that release acetylcholine chemical, then it produces the higher secretion of gastric juice.