What term refers to the processing of food that nourishes the individual cells of the body?

The concept of processing food that nourishes individual cells in the body aligns closely with the definition of metabolism. Metabolism encompasses all chemical reactions that occur within the body to maintain life, including the processes that convert food into energy, synthesize molecules for growth and repair, and eliminate waste products.

Digestion refers specifically to the mechanical and chemical breakdown of food into smaller components that can be absorbed. This process begins in the mouth and continues through the gastrointestinal tract, ultimately preparing the nutrients for absorption into the bloodstream.

Absorption is the next step following digestion; it describes how the small molecules derived from food are taken up into the bloodstream from the digestive tract. This is the stage where nutrients enter the body's circulation and become available to nourish the cells.

Excretion is the process of eliminating waste products from the body, which is unrelated to the nourishment of cells.

Thus, metabolism includes both digestion and absorption, emphasizing that it is the comprehensive process by which the body utilizes food for energy and growth, while digestion specifically pertains to the breakdown of food.