Assertion: arthropod's exoskeleton | /r/MadeOf | calcium
Facets:
value: predominately
type: DEGREE
value: for diatoms
type: PURPOSE
Source sentences:
text: They have a strong exoskeleton made of calcium and carbohydrates which protects them from predators.
text: The exoskeleton of molluscs (their ‘shell’) is predominately made of calcium and silica for diatoms.