Which of the following protects the inner lining of the stomach from the action of the acid under normal conditions ?

Mucus 

The correct answer is Option (2) –Mucus

The digestion in stomach is taken care of by the gastric glands present in the wall of the stomach. These release hydrochloric acid, a protein digesting enzyme called pepsin, and mucus.

The hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin.

The mucus protects the inner lining of the stomach from the action of the acid under normal conditions .