Assertion: cockroach's exoskeleton | /r/HasProperty | rigid
Facets:
value: by necessity
type: CAUSE
Source sentences:
text: Because the exoskeleton is rigid and cannot change size once it is “set” on the insect, cockroaches must get larger and grow by a process called “molting.
text: The exoskeleton is extremely sturdy and rigid by necessity.
text: The exoskeleton is not only rigid but flexible to allow the roach to crawl into tiny crevices.