Assertion: humpback whale's song | /r/CapableOf | change over a period of years
Facets:
value: slowly
type: MANNER
Source sentences:
text: Whales that inhabit the same area all sing the same song and each song changes slowly over a period of years.
text: Each population's song changes slowly over a period of years without repeating.
text: Each population's song changes slowly over a period of years without repeating.