Final answer:
Carbohydrates have two main functions: energy storage and structural components.
Step-by-step explanation:
Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen atoms. The family of carbohydrates includes both simple and complex sugars. Glucose and fructose are examples of simple sugars, and starch, glycogen, and cellulose are all examples of complex sugars.
The complex sugars are also called polysaccharides and are made of multiple monosaccharide molecules. Polysaccharides serve as energy storage and as structural components. For example, starch and glycogen are used for energy storage in plants and animals, respectively, and chitin forms the exoskeleton of insects.