Answer: chitin
Explanation:
An arthropod is an invertebrate animal that exhibit an exoskeleton that can be define as an external outer covering of the animals. The exoskeleton in the arthropods is made up of chitin. The hard outer exoskeleton plays many roles like it provides the protection to the animal against the predator, any environmental hazard and it is waterproof which means it does not allow the entrance of external water inside the body cover of the animal.
