The correct answer is Hydrochloric acid.The acid secreted by the gastric glands of human beings that helps in the digestion of food is Hydrochloric acid (HCI).Hydrochloric acid (HCI):The acid has a distinctively pungent smell.It is classified as strongly acidic and can attack the skin over a wide composition range.Hydrochloric acid was discovered by the alchemist Jabir ibn Hayyan around the year 800 AD.The hydrochloric acid secreted by the gastric glands facilitates the action of pepsin.Pepsin is an enzyme found in gastric juice that digests proteins.Pepsin was found by German physiologist Theodor Schwann.Pepsin affects only partial degradation of proteins into smaller units called peptides which are absorbed by the intestines or broken down further by the pancreatic enzymes.