Which type of carbohydrate is primarily used for energy storage in plants?

The correct choice is starch, as it serves as the primary carbohydrate for energy storage in plants. Starch is composed of long chains of glucose molecules and functions as a polysaccharide that plants synthesize through photosynthesis. When plants produce excess sugar during this process, they convert it into starch, which is stored in various parts of the plant, such as roots and tubers, providing a reserve of energy that can be utilized when needed.

In contrast, cellulose, while also a carbohydrate, primarily serves structural purposes in the plant cell walls and is not utilized for energy storage. Glycogen, although an efficient form of energy storage, is predominantly found in animals rather than plants. Dietary fiber, on the other hand, encompasses various plant components that are not fully digestible by the human digestive system, and while it includes cellulose, it does not function as an energy storage component in plants. Thus, starch stands out as the key storage carbohydrate in plants, storing energy efficiently until it is needed for growth and metabolic functions.