Assertion: crab's skeleton | /r/MadeOf | bone
Facets:
Source sentences:
text: The skeletons of bony fish are made of bone (duh), whereas those of cartilaginous fish are made of a flexible, bone-like substance called cartilage.
text: Whereas the skeletons of bony fish (the other main fish group) are made of bone, those of cartilaginous fish are made of a flexible substance called cartilage.