Chitin is a tough, flexible substance that forms the exoskeletons of many insects and crustaceans, like crabs and shrimp. It is a natural polymer, similar to cellulose in plants, and provides strength and protection to these creatures. Chitin is also found in the cell walls of some fungi, making it an important component in both the animal and fungal kingdoms. In addition to its structural role, chitin has various uses in science and industry. It can be processed to create chitosan, which is used in medical applications, water purification, and even as a food preservative. Its biodegradable nature makes it an eco-friendly alternative to many synthetic materials.