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In which part of the gastrointestinal tract does the majority of food digestion and absorption occur?

  1. Mouth

  2. Stomach

  3. Small intestine

  4. Large intestine

The correct answer is: Small intestine

The small intestine is the primary site for food digestion and absorption in the gastrointestinal tract. This is where digestive enzymes from the pancreas and bile from the liver work together to break down food into smaller, absorbable nutrients. The small intestine consists of three parts: the duodenum, jejunum, and ileum, each playing a specific role in processing nutrients. In the duodenum, the initial phase of digestion occurs, where chyme from the stomach mixes with digestive juices. The jejunum is primarily responsible for the absorption of carbohydrates, proteins, and fats, while the ileum mainly absorbs vitamins and bile acids. The structure of the small intestine, with its villi and microvilli, greatly increases the surface area, facilitating maximum nutrient absorption. In contrast, the mouth primarily initiates the digestive process through mechanical breakdown and salivary enzyme activity, but it is not where significant nutrient absorption takes place. The stomach enzymatically breaks down proteins and mixes food with gastric juices, but its role in absorption is limited to some water and alcohol. The large intestine is mainly involved in the absorption of water and electrolytes and the formation of solid waste, rather than the digestion and absorption of nutrients. Thus, the small intestine stands out as the key