Final answer:
Polysaccharides, which include starch, glycogen, and cellulose, are complex carbohydrates important for energy storage in plants and animals (starch and glycogen) and providing structural support in plants (cellulose).
Step-by-step explanation:
The substances that include sugars, starches, and cellulose are known as polysaccharides, which are complex carbohydrates consisting of long chains of monosaccharide units. Cellulose is a kind of polysaccharide that forms an integral part of plant cell walls and is used in the production of materials like paper and cardboard. Starch is another type of polysaccharide that plants use to store energy, and it's commonly found in foods like potatoes. Glycogen, also a polysaccharide, serves as the main form of energy storage in animals and fungi.
These polysaccharides are critically important to both plant and animal life. Cellulose provides structural integrity to plant cells, thereby contributing to the rigidity of plants. Starch and glycogen function as energy reserves in plants and animals, respectively, and play vital roles in maintaining energy homeostasis. Although all composed of glucose molecules, starch, glycogen, and cellulose differ structurally, leading to their unique properties and uses in living organisms.