Assertion: water snake | /r/CapableOf | play their role
Facets:
value: by reducing the number of bullfrogs
type: MANNER
Source sentences:
text: In the western parts of the US, where the large bullfrogs have become an invasive species, and are waging war against native frog breeds, the diamondback water snakes are playing their role by reducing the number of bullfrogs in those areas.