Carbohydrates are stored in plants and animals primarily in the form of (b) Starch and Glycogen. Starch serves as the main storage carbohydrate in plants, found in structures such as roots, tubers, and seeds. Glycogen, on the other hand, is the main storage carbohydrate in animals, stored primarily in the liver and muscles. While glucose is a simple sugar and a component of both starch and glycogen, cellulose is a structural carbohydrate found in plant cell walls and is not used for energy storage in either plants or animals.