Assertion: hedgehog's quill | /r/HasProperty | same stuff
Facets:
Source sentences:
text: These quills are made of keratin, the same stuff our hair and fingernails are made of.
text: These quills are made of keratin, the same stuff our hair and fingernails are made of.
text: These quills are made of keratin, the same stuff our hair and fingernails are made of.