Assertion: horseshoe crab's leg | /r/ObjectUse | used for breathing
Facets:
Source sentences:
text: It has six pairs of jointed legs and six leather-like flaps, called book gills, which are used for breathing and swimming.
text: The newly named, 425-million-year-old Dibasterium durgae looked roughly like a horseshoe crab from the top, though if you were to turn the arthropod over, you would have been greeted by a nest of double-branched legs used for both breathing and locomotion.