In the struggle to survive the ever hotter deserts of California，there are winners and losers.Among the losers are desert birds，whose populations have fallen among the heat stress of climate change.The winners，it turns out，are small burrowing mammals （穴居哺乳動物），which take refuge from the sun underground.Researchers noted that the stable mammals populations formed a striking contrast to the extremely bad condition of birds.
   But why？Birds had a higher evaporative（蒸發(fā)）heat loss.Birds were more exposed to the effects of warming，so they had higher energy costs to maintain their body temperature.However，mammals were able to reduce their body temperature by using burrows during the day.
   Temperatures have risen about 4 degrees Fahrenheit on average across the area studied，but the heat affects birds and small mammals differently.As part of the study，scientists modeled each species' body temperature and cooling needs under different desert conditions.To calculate that，they measured the conductivity（傳導率） of the animals' fur or feathers，and used information on their heat reducing behaviors.
   The models showed that in the fight against climate change，there was not a level playing field for furred and feathered desert animals.Cooling costs or the resources needed to maintain stable body temperature- -were about 3.3 times higher for birds than they were for small mammals，the study reported.
   Small mammals have shown this remarkable stability.It's really quite interesting that，in the same region，with the same level of climate change，these two species have responded very differently to the changes taking place.Insights into the status of different species can help scientists take steps to protect them，such as increasing fire prevention in high desert areas，and enhancing water sources in those areas.The study also demonstrates that climate change is already reshaping the California desert.

（1）Why can desert burrowing mammals survive better than desert birds？
A．Burrowing mammals prefer to live in deserts.
B．Burrowing mammals eat less during the day.
C．Burrowing mammals' caves are natural shelters.
D．Burrowing mammals live in the same community.
（2）What can we learn from the third paragraph？
A．Birds and small mammals respond differently to climate changes.
B．Birds in the desert were defeated by climate changes.
C．Animals living underground have higher cooling costs.
D．Temperature rise affects the burrowing mammals little.
（3）What is the possible meaning of the new finding？
A．Burrowing mammals may help birds during the day.
B．Governments will improve water quality.
C．Man will reshape the deserts to save themselves.
D．Scientists can save species with scientific means.
（4）What do we know from the text？
A．It's time to change the deserts into green fields.
B．Desert birds are more likely to survive in deserts.
C．Burrowing mammals' habitat needs improving greatly.
D．Burrowing mammals survive climate change underground.

【考點】說明文．

【答案】C；A；D；D