Chitin is also found in the exoskeletons of which organisms?

• A. Insects
• B. Mammals
• C. Fish
• D. Birds

Answer: (A)

Chitin is a tough, nitrogen-containing polysaccharide that forms the exoskeletons of many arthropods. Insects, as arthropods, have exoskeletons made of chitin, which provides protection and support while still allowing for growth through molting. Mammals rely on collagen-rich tissues, keratin in hair and nails, and bone for their structure—none of which involve chitin. Fish use mineralized bone and, in some cases, scales with different materials, and birds rely on keratin for feathers and beaks alongside bone. So, the exoskeletons characteristic of insects are the ones that contain chitin.