Assertion: squid's beak | /r/MadeOf | chitin
Facets:
value: mainly
type: DEGREE
Source sentences:
text: The mouth is equipped with a sharp, horny beak mainly made of chitin and cross-linked proteins, which is used to kill and tear prey into manageable pieces.
text: The mouth of the squid is equipped with a sharp horny beak mainly made of chitin  and cross-linked proteins, and is used to kill and tear prey into manageable pieces.