Digestive system of gastropods jaw structure can be ribbed or smooth: Some species have no jaw. Salivary glands plays primary role in the anatomical and physiological adaptations of the digestive system of predatory gastropods. Ducts from large salivary glands lead into the buccal cavity, and the oesophagus also supplies the digestive enzymes that help to break down the food. Salivary secretions lubricate the food and they also contain bioactive compounds. The mouth of gastropods opens into an oesophagus, which connects to the stomach. Because of torsion, the oesophagus usually passes around the stomach, and opens into its posterior portion, furthest from the mouth. In
Acidic oxide Acidic oxide Acidic oxides, or acid anhydrides, are oxides that react with water to form an acid, or with a base to form a salt. They are oxides of either nonmetals or of metals in high oxidation states. Their chemistry can be systematically understood by taking an oxoacid and removing water from it, until only an oxide remains. The resulting oxide belongs to this group of substances. An inorganic anhydride (a somewhat archaic term) is acid anhydride without an organic moiety. Acidic oxides are not Brønsted–Lowry acids because they do not donate protons; however, they are Arrhenius acids because they