Assertion: kudu's horn | /r/MadeOf | a layer of keratin
Facets:
value: around a core of bone
type: LOCATION
Source sentences:
text: Bovidae horns are made of a layer of keratin (the same material as human toenails and fingernails) around a core of bone, with a layer of cartilage in between, which can be removed to leave the hollow keratin horn.