Assertion: feather's bird | /r/HasAspect | specialized muscles
Facets:
value: to flap
type: PURPOSE
Source sentences:
text: For instance, a bird has light, hollow bones as well as an unusually efficient respiratory system and specialized muscles to flap and control its wings.
text: For instance, a bird has light, hollow bones as well as an unusually efficient respiratory system and specialized muscles to flap and control its wings.