(i) Mention the role of $HCl$ in the stomach, (ii) What function is served by the following?

(i) Mention the role of $HCl$ in the stomach, (ii) What function is served by the following?
(a) Gastric sphincter
(b) Anal sphincter

(i) $HCl$ kills bacteria in the stomach and provides acidic medium for activation of pepsin (enzyme required for protein digestion).
(ii) (a) The release of food from the stomach to small intestine is controlled by gastric sphincter.
(b) The release of undigested food from rectum through the anus is controlled by anal sphincter.