Assertion: shark's structure | /r/ObjectUse | used for mating
Facets:
Source sentences:
text: Like other elasmobranches, sawfish lack a swim bladder (instead controlling their buoyancy with a large oil-rich liver), have a skeleton consisting of cartilage, and the males have claspers, a pair of elongated structures used for mating and positioned on the underside at the pelvic fins.