Which organ is composed of the duodenum, jejunum, and ileum and absorbs nutrients?

• A. Stomach
• B. Esophagus
• C. Small intestine
• D. Large intestine

Answer: (C)

Nutrient absorption takes place primarily in the small intestine, which is made up of the duodenum, jejunum, and ileum. After food leaves the stomach as chyme, it enters the small intestine where digestion continues and nutrients are absorbed into the bloodstream. The duodenum mixes chyme with bile and pancreatic juices to break down fats and other nutrients, the jejunum is the main site where most nutrients are absorbed, and the ileum absorbs bile acids and vitamin B12. The small intestine’s lining has many folds, villi, and microvilli to maximize surface area for absorption.

The other options don’t fit because the stomach is where initial digestion occurs but is not composed of those sections; the esophagus transports food to the stomach without absorption; and the large intestine absorbs water and electrolytes rather than the bulk of nutrient absorption.