Assertion: exoskeleton | /r/MadeOf | chitin
Facets:
Source sentences:
text: Scorpions have an exoskeleton (external skeleton) made of chitin, a tough, protective, flexible molecule made of polysaccharide and nitrogen.
text: An exoskeleton is a tough, structural body armor made of chitin (a type of protein).
text: Their exoskeleton is made of chitin and proteins.
text: An exoskeleton is made of chitin which is a strong and hard material.