The correct options are
A Activation of inactive pepsinogen
D Protection from microorganisms
Gastric glands are present in the wall of stomach and their secretions are called gastric juices. Gastric Juice contains HCl, pepsinogen and mucus.
HCl performs the following functions:
→ Converts the inactive pepsinogen into active pepsin
→ Kills the microorganisms that enter along with the food.