TOEFL Reading: ETS-TOEFL阅读机经 - 63LAE4WMAH52K30OL$

Paragraph 2 implies which of the following about yellow-rumped caciques? A. They are comparatively unlikely to be harmed by the wasps that attack their predators. B. They are able to protect their nests without using colonies. C. Mixing active nests with abandoned nests is the least useful way of defending their nests. D. Most of their predators are members of other bird species.