On an average day, the trillions of cells in the human body perform many chemical processes

Which form of energy do those processes use directly?

ATP

Explanation:

ATP, adenosine triphosphate is the energy currency of cells. It has three terminal phosphate groups bonded by phosphoanhydride bonds. The reaction of hydrolysis of ATP into ADP and Pi has large negative free energy change and therefore, is a highly exergonic reaction. The energy released during ATP hydrolysis is used to cells to perform the energy-demanding processes. The chemical processes which require energy input are coupled to the ATP hydrolysis. Therefore, cells can use the energy of ATP hydrolysis to perform other chemical processes.