Which are the three regions of the small intestine and their primary roles?

• A. Jejunum – digestion; Duodenum – absorption; Ileum – absorption.
• B. Ileum – digestion; Duodenum – absorption; Jejunum – absorption.
• C. Duodenum – digestion; Ileum – absorption; Jejunum – absorption.
• D. Duodenum – absorption; Jejunum – digestion; Ileum – absorption.

Answer: (C)

The small intestine is organized so digestion happens mainly in the first segment and absorption takes place in the remaining sections. The duodenum is where chyme mixes with bile and pancreatic juices, driving the chemical digestion of proteins, fats, and carbohydrates. The middle portion, the jejunum, is where most nutrients are absorbed thanks to its high surface area from villi and microvilli. The last portion, the ileum, continues absorption and handles specialized tasks like reabsorbing bile acids and vitamin B12, which are essential for recycling and other bodily functions. So describing the first region as for digestion and the next two as for absorption captures how the small intestine distributes its work along its length.