Which organ reabsorbs water to form solid waste?

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

Answer: (C)

Water reabsorption to form solid waste happens in the large intestine. After most nutrients and much of the water are absorbed earlier in the digestive tract, the remaining material moves into the large intestine where water and electrolytes are reabsorbed, primarily by osmosis. This removal of water concentrates the waste into stool. The large intestine’s job is to turn this liquid mixture into a semi-solid form that can be excreted. In contrast, the esophagus and stomach mainly handle transport and initial digestion, with only minimal water reabsorption, while the small intestine absorbs most nutrients and a large portion of water but does not form solid waste.