What is the carbohydrate that makes up an exoskeleton?

The carbohydrate that primarily makes up an exoskeleton is chitin. Chitin is a long-chain polymer of N-acetylglucosamine, a derivative of glucose, and is found in the exoskeletons of arthropods such as insects and crustaceans, as well as in the cell walls of fungi. This tough and flexible material provides structural support and protection to these organisms.