Assertion: brittle star | /r/PartOf | the group of animals
Facets:
Source sentences:
text: Brittle stars and basket stars, sea lilies and feather stars, sea stars, sea daisies, sea urchins and sand dollars, and sea cucumbers all belong to the group of animals called echinoderms (ih-KYE-nuh-durhms), which means "prickly skin.