Assertion: sea urchin's symmetry | /r/HasProperty | radial
Facets:
Source sentences:
text: Sea urchins belonging to the Irregularia like thishave lost their spherical shape and their radial symmetry.
text: Because of this, many biologists believe that sea urchins were once ancestors to sessile organisms and thus, developed radial symmetry as an evolutionary adaptation to increase nutrient and gas exchange.