Assertion: viper's mouth | /r/HasProperty | closed
Facets:
Source sentences:
text: When the snake's mouth is closed, the fangs recede into a thin membrane and fold against the roof of the snake's mouth.
text: When the snake’s mouth is closed, the fangs are folded back and lie parallel to the roof of the mouth.
text: When the snakes mouth is closed the fangs fold into the back of its mouth and are covered with a membranous layer to "sheath" them.