Answer: ATP- ADT-ADP is a cycle.
Step-by-step explanation:
Adenosine triphosphate is like a charged battery and Adenosine diphosphate is a dead battery.
ATP is hydrolysed and the ADP and Pi is obtained by the addition of water and in response energy is released.
The ADP can be recharged as a battery and to get converted into ATP by the addition of the inorganic phosphate and this process releases energy and this cycle continues.