Which substance secreted by the body helps coat stomach and protects it from own acid?

The substance secreted by the body that helps coat the stomach and protects it from its own acid is called mucus. Mucus is a thick, viscous fluid produced by the mucous membranes that line the stomach and other parts of the digestive tract. It contains various substances, such as glycoproteins and mucins, that form a protective barrier against the acidic environment of the stomach. This layer of mucus helps to protect the stomach lining from the corrosive effects of hydrochloric acid and enzymes involved in digestion. It also aids in lubricating the passage of food through the digestive tract and facilitates digestion.