Grassland songbirds often nest in the same grassland-wetland complexes as waterfowl, particularly in a certain part of those complexes, namely, upland habitats surrounding wetlands. Although some wildlife management procedures directed at waterfowl, such as habitat enhancement or restoration, may also benefit songbirds , the impact of others, especially the control of waterfowl predators, remains difficult to predict. For example, most predators of waterfowl nests prey opportunistically on songbird nests, and removing these predators could directly increase songbird nesting success. Alternatively, small mammals such as mice and ground squirrels are important in the diet of many waterfowl-nest predators and can themselves be important predators of songbird nets. Thus. Removing waterfowl-nest predators could affect songbird nesting success through subsequent increases in small-mammal populations.

In 1995 and 1996, researchers trapped and removed certain waterfowlnest predators. primary raccoons and striped skunks, then observed subsequent survival rates for songbird nests. Surprisingly. They observed no significant effect on songbird nesting success. This may be due to several factors. Neither raccoons nor striped skunks consume ground squirrels, which are important predators of songbird nests. Thus, their removal may not have led to significant increases in populations of smaller predators. Additionally, both raccoons and striped skunks prefer wetlands and spend little time in upland habitats; removing these species may not have increased the nesting success of songbirds in the uplands enough to allow detection.

Which of the following best describes the function of the sentence "Neither raccoons...songbird nests" (highlight) in the context of the passage as a whole?

It raises questions about the validity of a theory described in the first paragraph.

It points out an oversimplification that is inherent in the argument presented in the first paragraph.

It introduces information that may help explain the results of the experiment that are presented earlier in the paragraph.

It provides a specific example of the type of data collected in the experiment described earlier in the paragraph.

It anticipates a potential objection to the conclusions drawn by the researchers involved in the experiment described earlier in the paragraph.


登录注册 后可以参加讨论