Answer: Acid in the stomach
Explanation: Food digestion begins in the mouth where food is digested, except by chewing, also by the salivary amylase enzyme. The fact that there is a high concentration of acid in the stomach, that is, acidic environment, stops the digestion of food by the salivary enzyme amylase. The usual stomach acidity is between 1 and 2 pH, which is quite acidic. Such acidity causes a change in the structure of the salivary enzyme amylase, which, when it enters the stomach, ceases to have a function for digestion.
