What process involves the breakdown of food into smaller components?

The process that involves the breakdown of food into smaller components is digestion. Digestion is essential because it transforms whole food into simpler molecules that the body can utilize for energy, growth, and repairing tissues. This process begins in the mouth with mechanical and chemical processes, continues in the stomach and small intestine where enzymes and acids further break down the food, and ultimately prepares the nutrients for absorption into the bloodstream.

While excretion refers to the removal of waste products from the body, and metabolism encompasses all chemical reactions in the body, including anabolism (building up) and catabolism (breaking down), it is digestion that specifically targets the breakdown of food. Absorption follows digestion and deals with the uptake of these smaller nutrient molecules into the cells. Thus, digestion is the correct answer as it directly addresses the process of breaking down food into its smaller components.