All organisms use ADP to store energy?
They use ATP as an energy source (ADP is left over after the energy is used).
There is no storage there.
Animals use fat to store energy, plants use starch.
All living organisms need energy to survive. This energy comes from the foods that they eat. However, in order to meet the demands of energy required throughout the day the body of the organism must store its energy for use later on. Lipids and carbohydrates are the compounds used in these organisms to store energy.