Assertion: echinoderm's skeleton | /r/HasProperty | calcareous plates
Facets:
value: to protect themselves
type: PURPOSE
Source sentences:
text: Echinoderms have a mesodermal skeleton composed of calcareous plates or ossicles.
text: Echinoderms have a skeleton composed of calceous plates to protect themselves.
text: Echinoderms have a mesodermal skeleton composed of calcareous plates or ossicles.