Assertion: penguin's feather | /r/HasProperty | coated with a type of oil
Facets:
Source sentences:
text: They also have a layer of woolly down under the feathers that are coated with a type of oil that makes them waterproof.
text: They also have a layer of woolly down feathers, under the outer veined feathers that are coated with a type of oil that makes them waterproof.
text: They also have a layer of woolly down under the feathers that are coated with a type of oil that makes them waterproof.