Assertion: mantis's eye | /r/HasProperty | rigid
Facets:
value: completely
type: DEGREE
value: due to their unusual composition
type: CAUSE
Source sentences:
text: Due to their unusual composition, trilobite eyes were completely rigid and could not be adjusted to focus; instead, the trilobite corrected its focus with an internal eye mechanism which not only solved any potential problems caused by the mineral lens, but also gave the trilobite such good vision, that it could keep both close and distant objects in focus at the same time.