Assertion: black rhinoceros's horn | /r/MadeOf | same type of substance
Facets:
Source sentences:
text: The horn of the rhino is not made of bone but is actually made from the same type of substance that hair and fingernails are made of: keratin.
text: The horn of the rhino is not made of bone but is actually made from the same type of substance that hair and fingernails are made of: keratin.