Assertion: early sponge | /r/HasAspect | organic skeletons
Facets:
value: entirely
type: DEGREE
Source sentences:
text: Early Cambrian sponge spicules described in this paper, as well as some other early Paleozoic sponge spicules, have relatively large proportions of organic material, indicating that early sponges may have had weakly biomineralized spicules or entirely organic skeletons, which unlike fully biomineralized sponge spicules, were less amenable to fossilization.