In which part of the digestive system is water primarily absorbed?

• A. Colon
• B. Stomach
• C. Duodenum
• D. Ileum

Answer: (A)

Water absorption happens most effectively in the large intestine, particularly the colon. After most nutrients have been absorbed in the small intestine, the remaining indigestible material moves into the colon, where the lining reclaims water and electrolytes by osmosis as ions are transported. This reclaiming of water concentrates the waste into stool and helps regulate hydration.

The small intestine handles digestion and the bulk of nutrient absorption, with the duodenum initiating chemical digestion and the ileum absorbing specific things like bile acids and vitamin B12. The stomach does some limited water absorption, but not the main role. So the colon is the primary site for absorbing the majority of water.