Assertion: otter's tail | /r/CapableOf | act as rudder
Facets:
Source sentences:
text: Beavers are well-adapted for semi-aquatic life, with thick waterproof fur, a flattened tail that acts as a rudder, and closable nostrils and ears, as well as a transparent eye membrane.
text: The long tail is flattened in some species and acts as a rudder.