(a) What is the role of hydrochloric acid in our stomach?
(b) what is the function of enzymes in the human digestive system?

a) Hydrochloric acid plays a major role in the process of digestion. It makes the medium of gastric juice acidic so that the enzyme pepsin can digest the proteins properly and also kills any bacteria that might have entered the stomach with food.

(b) Enzymes play a lead role in the human digestive system. They help in the breaking down of complex organic food materials into simpler forms.