Assertion: sea urchin's system | /r/AtLocation | echinoderm
Facets:
Source sentences:
text: The sea urchin is the first animal with a sequenced genome that (1) is a free-living, motile marine invertebrate; (2) has a bilaterally organized embryo but a radial adult body plan; (3) has the endoskeleton and water vascular system found only in echinoderms; and (4) has a nonadaptive immune system that is unique in the enormous complexity of its receptor repertoire.