Assertion: porcupine's quill | /r/CapableOf | become erect
Facets:
Source sentences:
text: When either type of porcupine is threatened, its quills become erect, which makes the animal appear larger and more dangerous to predators.
text: When attacked by a predator, a porcupine becomes stressed and the muscles around the connective tissue tighten and cause the quills to become erect.