Which portion of the digestive tract absorbs most of the nutrients?

The portion of the digestive tract that absorbs most of the nutrients is the ileum. The ileum is the final section of the small intestine, where the absorption of nutrients, minerals, and vitamins is optimized. It is specifically designed for nutrient absorption, featuring a large surface area due to villi and microvilli, which enhance its capacity to absorb essential nutrients from digested food.

Although the duodenum does play a significant role in digestion and some absorption—particularly of iron and calcium—it is primarily responsible for the chemical breakdown of food through the action of digestive enzymes and bile. The majority of nutrient absorption occurs later in the ileum.

Other sections of the digestive tract, such as the stomach, primarily focus on mechanical and chemical digestion rather than nutrient absorption, while the cecum is involved in the absorption of water and electrolytes and acts as a site for fermentation of undigested materials, rather than being a primary location for nutrient absorption. Thus, the ileum is the correct answer as it is the part of the digestive system where the bulk of nutrient absorption occurs.