Assertion: plesiosaur's skeleton | /r/MadeOf | cartilage
Facets:
Source sentences:
text: The skeletons of cartilaginous fishes such as sharks and rays are made of cartilage, a material that is more flexible than bone.
text: Sharks have skeletons made of cartilage that are typically not preserved in the fossil record and so the jaws of megalodon and a few trace fossils are all paleontologists have to build their hypotheses.