Assertion: arthropod's structure | /r/MadeOf | clear
Facets:
Source sentences:
text: Some have hard structures which consist of crystalline (like crystal, clear or transparent) materials while others have an outer covering called a cuticle, as in arthropods, which is made out of chitin (a nitrogen-containing polysaccharide, related chemically to cellulose, that forms a semitransparent horny substance).