Read the given passage and answer the questions that follow.
Beneath the snow lies the subnivium (from the Latin nivis for snow, and sub for below), a small, protected area that is insulated and maintains a constant temperature. This microhabitat turns traditional thinking about snow on its head. Thanks to the emerging field of winter ecology, we now know that snowy environments have lives of their own. "Without snow, plant and animal life would be completely different," says biologist Jonathan Pauli of the University of Wisconsin-Madison. Pauli and scientists such as Ben Zuckerberg, are members of a new breed of researchers called winter ecologists who study the relationships among animals, plants and their snow-covered environments.
Their studies have shown that tiny mammals like shrews don't migrate but spend their winters in the subnivium. For some of the tiniest forms of life - fungi, invertebrates, soil bacteria and plant roots- snow maintains a mild winter temperature in which they can survive, compared to the killing cold up above. Plants and soil benefit from this layer because the lack of a hard frozen surface lets plant roots function. The active fungi release important nutrients to plants. As the temperature warms, the snow slowly melts and provides water for spring flowers. On an average, snow covers almost 18 million square miles of the planet each year. However, climate change is upsetting that chilly balance. Winter ecologists are studying how the lack of snow cover directly affects the ecology of many subnivium ecosystems, exposing organisms to temperatures for which they are not adapted.
Solution
To answer the "main idea" of the paragraph correctly, we have to skim through the passage and especially pay attention to the concluding paragraph, and make sure it is encapsulated in the main idea answer.
Option C: Correct. The passage mentions about "subnivium" which is the hidden world beneath snow, the concluding paragraph mentions that climate change is adversely affecting winter snow. This option encapsulates both the aspects and hence, is right.
Option A: Incorrect. "Thanks to the emerging field of winter ecology, we now know that snowy environments have lives of their own..." this line does mention that winter ecology which has subnivium is an emerging field and new researchers are studying it- the paragraph does not explicitly mention any "creative approaches", moreover, it is not the main idea, it is used to introduce a topic.
Option B: Incorrect. The last paragraph mentions sufficient information about survival of plants and animals beneath the snow and nowhere it is mentioned in the passage that we know "very little" about them.
Option D: Incorrect. It is not mentioned that the field of "winter ecology" has emerged because of climate change. Winter ecology is also mentioned above as a field to study subnivium as well. So it is clear that winter ecology as a field did not emerge to study climate change as it studies other things as well.
