Assertion: penguin's flipper | /r/HasProperty | stiff
Facets:
Source sentences:
text: Wings: Penguin wings have been converted into efficient flippers that are small and stiff.
text: Their strong flippers and torpedo-shaped bodies allow them to power through the water, while their black and white bodies act as camouflage (from above, their black backs blend in with deep water, while from below their white bellies blend in with the light surface).