Answer: Starch
Step-by-step explanation:
The energy that is instant used by the plants are in the form of carbohydrates. This is converted into adenosine tri phosphate which is used by the plants for various types of cellular processes.
The energy in the plants is stored in the form of starch in the roots and various parts of the plant body.
The stored form of food is starch which is used at the time of scarcity. This stored food is in the form of fruits and is stored in the form of roots, stem et cetera.