Assertion: sea urchin | /r/HasAspect | spine
Facets:
Source sentences:
text: Why Do Sea Urchins Have Spines?
text: Even though sea urchins have spines, they have a lot of predators.
text: Sea urchins have spines and tubes that serve roles in acquiring food, protection and respiration.
text: Most sea urchins have spines that are about an inch long (give or take a bit).