When molecules are broken apart in respiration

a. the heat produced is used to drive biological reactions

b. the oxygen in the compounds that are broken apart is used as an energy source

c. the energy released in respiration is channeled into molecules of ATP

d. ATP is converted into ADP

e. ADP is released as a waste product

the energy released in respiration is channeled into molecules of ATP

Explanation:

During cellular respiration molecules are gradually broken. Energy released during the reaction is captured by the energy-carrying molecule ATP (adenosine triphosphate). Energy released from the food molecules is used to join together a phosphate group with the molecule adenine diphosphate (ADP), to create the ATP molecule and store energy