Which statement about mechanical digestion is true?

• A. It breaks down food by chemical reactions
• B. It occurs only in the mouth
• C. It physically breaks down food into smaller pieces
• D. It occurs after absorption

Answer: (C)

Mechanical digestion is the physical breakdown of food into smaller pieces. Through actions like chewing in the mouth and the churning, mixing motions in the stomach, food is reduced in size without chemical changes, which prepares it for chemical digestion by increasing surface area for enzymes to act later. That’s why the correct statement is that mechanical digestion physically breaks down food into smaller pieces. The other ideas describe chemical digestion, not mechanical, and mechanical processes also occur beyond the mouth, and must happen before absorption, not after.