Which polysaccharide serves as an energy polymer in plants?

Starch serves as the primary energy storage polysaccharide in plants. It is composed of long chains of glucose molecules, allowing plants to store energy in a stable form that can be easily converted back into glucose when needed for metabolic processes. The structure of starch, which includes amylose and amylopectin, enables it to be broken down efficiently by enzymes when the plant requires energy, particularly during periods of growth or in response to environmental stresses.

Cellulose, while also a polysaccharide, primarily serves as a structural component in plant cell walls and is not utilized as a direct energy source. Glycogen is the energy storage polysaccharide found in animals, not plants. Chitin is a structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi, and it does not function in energy storage for plants. Therefore, starch is correctly identified as the energy polymer in plants.