Assertion: robin | /r/CapableOf | make sure
Facets:
Source sentences:
text: They worked hard to try to make sure that both Old Green and Old Blue, the two original females, contributed genetics to the population; but in the end all of the surviving Black Robins were descended from Old Yellow, the only productive male, and Old Blue, the female who had already been eight years old when the population was down to five birds.