Question

The acid present in the stomach
A. Kills the harmful bacteria that may enter the gut with food
B. Protects the stomach lining from harmful substances
C. Digests starch into simpler sugars
D. Makes the medium alkaline.

Answer 1

Hint: Stomach is a muscular organ present in the gastrointestinal tract of animals. It is an elastic structure and functions to digest food particles. It secretes several enzymes and an acid which facilitate the process of digestion.

Complete answer:
Stomach is present in the gastrointestinal cavity of animals. The oesophagus or the food pipe connects the stomach to the mouth cavity. The rear end of the stomach is connected to the small intestine. The stomach plays a central role in digestion. It receives the mashed food from the oesophagus and churns them to convert into chyme or partially digested food. While churning, the stomach secretes gastric juices and a mild acid called Hydrochloric acid into the chyme.
Hydrochloric acid plays an important role in digestion by:
-By killing microorganisms present in the food
-Activates pepsinogen to form pepsin, which in turn digests proteins.

Lowering the pH of the stomach that creates an ideal medium for pepsin to function.
The lining of the stomach is protected from the Hydrochloric acid by a mucosal barrier.
Starch is converted to simpler sugars by salivary amylase and pancreatic amylase in the mouth and duodenum, respectively.
Hydrochloric acid, being an acid, does not make the medium alkaline in the stomach. Instead, it makes the medium acidic that helps certain enzymes to function properly.
Therefore, we can conclude that the acid in the stomach helps to kill harmful microorganisms that come in with food particles.

Hence, the correct answer is option (A).

Note: Stomach is the major digestive organ of the body. It secretes enzymes and Hydrochloric acid that helps to digest food. The stomach churns the food by a movement called peristalsis to break down food particles. The acid secreted by stomach functions to kill microorganisms, activate enzymes and provide the required pH for enzymes to function.