Industrial activity is often assumed to be a threat to wildlife, but that isn’t always so. Consider the silver-studded blue butterfly (Plebejus argus): as forest growth has reduced grasslands in northern Germany, many of these butterflies have left meadow habitats and are now thriving in active limestone quarries. In a survey of multiple active quarries and patches of maintained grassland, an ecologist found silver-studded blue butterflies in 100% of the quarries but only 57% of the grassland patches. Moreover, butterfly populations in the quarries were four times larger than those in the meadows.
Which choice best describes the function of the underlined portion in the text as a whole?
It challenges a common assumption about the species under investigation in the research referred to in the text.
It introduces discussion of a specific example that supports the general claim made in the previous sentence.
It suggests that a certain species should be included in additional studies like the one mentioned later in the text.
It provides a definition for an unfamiliar term that is central to the main argument in the text.
Choice B is the best answer because it most accurately describes how the underlined portion functions in the text as a whole. The first sentence presents the general claim that industrial activity is not always a threat to wildlife. The underlined portion of the sentence that follows suggests that the silver-studded blue butterfly is an example of wildlife thriving in areas of industrial activity: active limestone quarries. Thus, the function of the underlined portion is to introduce a specific example in support of the general claim in the previous sentence.
Choice A is incorrect. Although the first sentence indicates that “industrial activity is often assumed” to harm wildlife, in the case of the silver-studded blue butterfly the text mentions neither an assumption about this species nor any challenge to such an assumption. Choice C is incorrect because the text mentions only one study: the “survey.” Additional studies are not mentioned in the text. Choice D is incorrect because neither the underlined portion nor any other portion of the text provides a definition for any of the terms used in the text’s argument.