Assertion: echinoderm's skeleton | /r/MadeOf | porous plates
Facets:
Source sentences:
text: The others, despite some spectacular differences in appearance, share a few common traits – a calcite skeleton made of porous plates (reduced to tiny spicules in the holothurians), a remarkable ‘water vascular system’ that uses hydraulics to manipulate large numbers of tiny tube feet, and… wait for it… five-fold symmetry.