GRE Reading Comprehension: Maggoosh-GRE阅读Maggoosh - 455N3N1A4LZ5PJ08N

In 1995, ecologists started to reintroduce the wolf into Yellowstone Park, where the wolf had been eliminated intentionally half a century earlier. Rangers expected a rise in the number of wolf would place limits on the elk population and on the populations of many mid-size mammals. One unexpected consequence was a dramatic rise in the population of foxes, which in turn helped to control many rodent populations.