CAIE Checkpoint Science – Biology: Digestive System — covers physical and chemical breakdown of food, tooth types and functions, enzyme action (amylase, pepsin, lipase) and their sources, peristalsis in swallowing, roles of stomach, duodenum, liver, pancreas, and small intestine in digestion, nutrient absorption, and egestion of undigested material through the large intestine, rectum, and anus.