Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. Endothermic reactions absorb energy, and exothermic reactions release energy. Answer: atp or adenozine triphosphate
What molecule is used for most energy functions in organisms?