Dear Student,
Both plants and animals use carbohydrates as a source of energy essential to carry out normal functions such as growth,movement,metabolism.Carbohydrate store energy in the form of starch which,depending on the type of carbohydrate provide either complex or simple sugars.Plants manufacture their own carbohydrate through photosynthesis,using the energy absorbed from light to combine carbon dioxide and water into more complex organic molecules.
The main function of carbohydrate in plants are:
(i) Polysaccharides such as starch serve as storage molecules
(ii) Cellulose,a polysaccharide is used to build the cell wall.
Regards.