English Language · English

Which choice best describes the function of the underlined portion in the text as a whole? 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.