Which process breaks down ingested food to simple molecules?

Which process breaks down ingested food to simple molecules?

• A. Digestion
• B. Metabolism
• C. Excretion
• D. Growth

Answer: (A)

The main idea here is digestion—the process that breaks down ingested food into simple, absorbable molecules. Digestion includes mechanical actions like chewing and stomach churning, plus chemical actions where enzymes and acids hydrolyze food into basic building blocks. Carbohydrates are turned into simple sugars, proteins into amino acids, and fats into fatty acids and glycerol, all of which can be absorbed through the walls of the small intestine into the bloodstream. Metabolism, in contrast, covers all of the body's chemical reactions, including both breakdown and synthesis. Excretion is the elimination of waste, and growth refers to increasing size or mass. So digestion is the step that converts food into the small molecules the body can use.

The main idea here is digestion—the process that breaks down ingested food into simple, absorbable molecules. Digestion includes mechanical actions like chewing and stomach churning, plus chemical actions where enzymes and acids hydrolyze food into basic building blocks. Carbohydrates are turned into simple sugars, proteins into amino acids, and fats into fatty acids and glycerol, all of which can be absorbed through the walls of the small intestine into the bloodstream. Metabolism, in contrast, covers all of the body's chemical reactions, including both breakdown and synthesis. Excretion is the elimination of waste, and growth refers to increasing size or mass. So digestion is the step that converts food into the small molecules the body can use.