What type of metabolism involves the breakdown of molecules to release energy?

The correct choice is catabolism, which is the process that involves the breakdown of larger molecules into smaller ones, resulting in the release of energy. This energy is released because the bonds within the molecules are broken, allowing the stored chemical energy to be harnessed for various cellular activities. Catabolism plays a vital role in providing the energy needed for essential physiological processes, as it helps fuel activities such as muscle contraction, nerve impulse conduction, and the synthesis of new molecules.

The other choices pertain to different metabolic processes. Anabolism refers to the constructive phase of metabolism wherein smaller molecules are assembled into larger, more complex ones, often requiring input of energy. Synthesis generally describes the process of creating new compounds, which may involve anabolic reactions. Resynthesis is similar and often describes the re-forming of molecules or compounds after they have been broken down or altered.