The gastric mucosa secretes the inactive enzyme pepsinogen and hydrochloric acid (HCl). In the presence of HCl, the active enzyme pepsin is produced. Pepsin digests proteins into shorter polypeptides. The high concentration of HCl from the parietal cells makes gastric juice very acidic, with a pH of less than 2.he gastric mucosa secretes the inactive enzyme pepsinogen and hydrochloric acid (HCl). In the presence of HCl, the active enzyme pepsin is produced. Pepsin digests proteins into shorter polypeptides. The high concentration of HCl from the parietal cells makes gastric juice very acidic, with a pH of less than 2.
Coral reef. Coral reef, ridge or hummock formed in shallow ocean areas by algae and the calcareous skeletons of certain coelenterates, of which coral polyps are the most important. A coral reef may grow into a permanent coral island.
The coral reef off the coast of Queensland, Australia, in the Coral  Sea is the Great Barrier Reef. It is the world's largest reef  system, composed of over 2,900 individualâ¦ reefs and stretches for  over 1,400 miles over an area of about 133,000 square miles.