What process involves breaking down complex chemicals into components and reassembling them into larger molecules?

The correct choice is metabolism, as it encompasses the entire range of biochemical processes that occur within living organisms to maintain life. Metabolism is divided into two primary components: catabolism and anabolism. Catabolism refers to the breaking down of complex molecules into simpler ones, releasing energy in the process. Anabolism involves using the energy produced during catabolism to synthesize larger molecules from smaller units.

Therefore, while metabolism includes both breaking down and building up processes, the specific function of breaking down complex chemicals and reassembling them falls under the umbrella of metabolic processes. It is important to recognize how these processes work together to support cellular function and energy balance in living organisms.