<Ol> <Li> Ingestion: placing food into the mouth (entry of food in the digestive system), </Li> <Li> Mechanical and chemical breakdown: mastication and the mixing of the resulting bolus with water, acids, bile and enzymes in the stomach and intestine to break down complex molecules into simple structures, </Li> <Li> Absorption: of nutrients from the digestive system to the circulatory and lymphatic capillaries through osmosis, active transport, and diffusion, and </Li> <Li> Egestion (Excretion): Removal of undigested materials from the digestive tract through defecation . </Li> </Ol> <Li> Ingestion: placing food into the mouth (entry of food in the digestive system), </Li> <Li> Mechanical and chemical breakdown: mastication and the mixing of the resulting bolus with water, acids, bile and enzymes in the stomach and intestine to break down complex molecules into simple structures, </Li> <Li> Absorption: of nutrients from the digestive system to the circulatory and lymphatic capillaries through osmosis, active transport, and diffusion, and </Li>

The main chemical activity of the stomach is to begin the digestion of