Assertion: echinoderm | /r/CapableOf | keep water
Facets:
Source sentences:
text: They serve an important function in digesting dead plant material on the ocean floor and thereby keeping waters clean.
text: Echinoderms all live in water and are predators or scavengers, the underside of the animal has a mouth and their arms are used to pry open shelled prey such as mollusks.