Assertion: sea slug's shell | /r/MadeOf | protein
Facets:
Source sentences:
text: Sea slugs, like nudibranchs and sea hares, do not have a shell, although they may have an internal shell made of protein.
text: The clade Anaspidea, commonly known as sea hares (Aplysia species and related genera), are medium-sized to very large opisthobranch gastropod molluscs with a soft internal shell made of protein.
text: Sea hares have an internal shell made of protein and nudibranchs shed their shell after their larval stage.