The inner lining of the stomach is protected from hydrochloric acid by mucus.
Explanation: Mucus is a thick, slippery substance secreted by the stomach lining cells that acts as a barrier, protecting the stomach from the corrosive nature of hydrochloric acid.
Why other options are incorrect:
Pepsin:
Pepsin is an enzyme present in the stomach that helps digest proteins. While it is produced in the stomach, its function is not to protect the stomach lining from hydrochloric acid; rather, it works with the acid to break down food.
Salivary amylase:
Salivary amylase is an enzyme found in saliva, not the stomach. Its primary function is to start the digestion of carbohydrates.
Bile:
Bile is a fluid produced by the liver and stored in the gallbladder. It helps digest fats in the small intestine, not the stomach.