AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Mouth: Food is crushed by teeth and mixed with saliva secreted by salivary glands. Saliva contains salivary amylase which breaks down starch into simple sugars. The tongue helps mix food thoroughly.
Oesophagus: Food travels down to the stomach through peristaltic movements (rhythmic muscle contractions).
Stomach: Gastric glands secrete hydrochloric acid, pepsin (protein-digesting enzyme), and mucus. HCl creates an acidic medium for pepsin to act; mucus protects the stomach lining.
Small Intestine: Site of complete digestion. Bile from the liver emulsifies fats and neutralises acid. The pancreas secretes trypsin (proteins) and lipase (fats). Intestinal juice finally converts proteins → amino acids, carbohydrates → glucose, fats → fatty acids and glycerol. Finger-like villi absorb digested food into the bloodstream.
Large Intestine: Absorbs water from undigested material; remaining waste is expelled through the anus.
Source: Chapter 5, Section 5.2.4 — Nutrition in Human Beings
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Examiners expect a clear organ-by-organ flow with the specific enzyme/secretion named at each stage. Key terms to include: salivary amylase, pepsin, HCl, bile (emulsification), trypsin, lipase, villi, peristalsis. Avoid vague phrases like "digestive juices help digest food" — always name the enzyme and what it acts on. Five organs = roughly one point each, fitting the 5-mark format perfectly.