Adenosine triphosphate (ATP) is a complex molecule which provides energy to the cells. This molecule is present in all the living organisms. The chemical energy which is obtained by the body by the breakdown of the food is captured by the ATP (Adenosine Triphosphate) molecules. This captured chemical energy is then transferred by it in order to fuel different body processes.
Hence, the answer is ATP (Adenosine Triphosphate).