Assertion: porcupine's spine | /r/HasProperty | coated with thick plates of keratin
Facets:
Source sentences:
text: Their spines are modified hairs coated with thick plates of keratin that are used to defend them from predators.
text: The animal's quills or spines take on many forms, depending on the type, but all are hairs coated with thick plates of keratin, and they are in the skin musculature.