Assertion: brush's hair | /r/HasProperty | natural
Facets:
Source sentences:
text: While natural boar bristle brushes contain natural hair that would take in moisture as would other types of natural hair so the bristles can twist or curl if dampened.
text: Paint brushes are made from stiff or soft hairs, which can be either natural hairs or synthetic fibers.
text: Initially, synthetic brushes were of dubious quality and the only advantage they had over natural hairs was that the brushes were cheaper.