Assertion: sand dollar's underside | /r/HasProperty | flat
Facets:
Source sentences:
text: In these urchins, the upper surface of the body is slightly domed, but the underside is flat, while the sides are devoid of tube feet.
text: In these urchins, the upper surface of the body is slightly domed, but the underside is flat, while the sides are devoid of tube feet.