Assertion: sponge's spicule | /r/HasProperty | structural elements
Facets:
Source sentences:
text: Spicules: structural elements found in most sponges that provide structural support, like a skeleton.
text: Most sponges are too rough for general use due to their structural spicules composed of calcium carbonate or silica.
text: Spicules are structural elements found in most sponges.