Which action is a typical example of mechanical digestion?

Which action is a typical example of mechanical digestion?

• A. Chewing
• B. Enzyme action
• C. Acid secretion
• D. Absorption

Answer: (A)

Mechanical digestion is the physical breaking down of food into smaller pieces without changing its chemical structure. Chewing fits this description because the teeth grind and tear food, producing smaller particles and increasing the surface area for the next stage. This action also blends the food with saliva to form a manageable bolus, preparing it for chemical digestion later on. The other options involve chemical changes: enzyme action uses catalysts to split molecules, acid secretion chemically digests food, and absorption is the uptake of nutrients after digestion rather than breaking them down.

Mechanical digestion is the physical breaking down of food into smaller pieces without changing its chemical structure. Chewing fits this description because the teeth grind and tear food, producing smaller particles and increasing the surface area for the next stage. This action also blends the food with saliva to form a manageable bolus, preparing it for chemical digestion later on. The other options involve chemical changes: enzyme action uses catalysts to split molecules, acid secretion chemically digests food, and absorption is the uptake of nutrients after digestion rather than breaking them down.