What are the polysaccharides that primarily come from plants?

Starches are polysaccharides that primarily come from plants and serve as a major energy storage form for them. Plants synthesize starch from glucose molecules through photosynthesis, and it is found in various plant-based foods such as potatoes, corn, and grains. Starch consists of two components: amylose and amylopectin, which provide a readily accessible source of energy for both plants and humans when consumed.

Cellulose, while also a polysaccharide derived from plants, serves primarily as a structural component in the cell walls of plants rather than as an energy storage molecule. Glycogen is a polysaccharide found mainly in animals as a storage form of glucose, and chitin is typically found in the exoskeletons of arthropods and is not a plant polysaccharide. Therefore, starch is the most relevant answer as it directly relates to energy storage in plants.