Which of the following is an accessory organ of digestion?

• A. Stomach
• B. Esophagus
• C. Mouth
• D. Liver

Answer: (D)

An accessory organ of digestion is a structure that assists the digestive process but isn’t part of the actual food-passing tube of the digestive tract. The liver fits this role because it produces bile, a digestive juice that helps break down fats, and releases it into the small intestine via ducts. The mouth, esophagus, and stomach are components of the alimentary canal itself, where food enters, moves along, and is chemically and mechanically processed. By contrast, the liver’s job is to support digestion from outside the food tube, making it the correct choice.