The process of breaking down food into smaller molecules.

• A. Digestion
• B. Nutrients
• C. Absorption
• D. Metabolism

Answer: (A)

Digestion is the process of breaking down food into smaller molecules. This involves both mechanical actions, like chewing and stomach churning, and chemical actions, such as enzymes and acids that split large molecules into smaller units—sugars from carbohydrates, amino acids from proteins, and fatty acids with glycerol from fats. Those smaller molecules are the forms that can be absorbed and used by the body. Nutrients are the substances your body needs or derives from digested food, but they’re the end products you obtain after digestion and absorption. Absorption is the next step, where these digested molecules cross the intestinal lining into the blood or lymph. Metabolism refers to the set of cellular chemical reactions that use those nutrients to produce energy and build new tissues. So the option that best fits “the process of breaking down food into smaller molecules” is digestion.