题干

图是我国鄂尔多斯(中部某地)地区地质历史时期气候变化与自然地带摆动关系示意图。据图和所学知识回答下列各题。

【小题1】该地区自然地带                                         
A.呈西北—东南方向延伸B.数量的增加与热量相关
C.数量的减少与水分相关D.数量的变化与地形有关
【小题2】该地区                                                

A:湿润期来自西部的水汽增加,使自然地带向西部摆动

B:湿润期森林草原农牧业带扩大,可以大规模进行开垦

C:干燥期沙地面积有扩大趋势,应注意营建防护林体系

D:短时期内发生湿润期和干燥期转变是受全球变暖影响

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答案(点此获取答案解析)

C

同类题2

阅读理解

    Grey clouds move as low as smoke over the treetops at Lolo Pass. The ground is white. The day is June 10.It has been snowing for the past four days in the Bitterroot Mountains.Wayne Fairchild is getting worried about our trek over the Lolo Trail-95 miles from Lolo Montana to Weippe in Idaho, across the roughest country in the West. Lewis and Clark were nearly defeated 200 years ago by snowstorms on the Lolo. Today Fairchild is nervously checking the weather reports. He has agreed to take me across the toughest, middle section of the trail.

    When Lewis climbed on top of Lemhi Pass,140 miles south of Missoula, on Aug.12,1805,he was astonished by what was in front of him; "high mountain chains still to the West of us with their tops partially covered with snow."Nobody in what was then the US knew the Rocky Mountains existed, with peaks twice as high as anything in the Appalachians back East.

    Today their pathway through those mountains holds more attraction than any other ground over which they traveled, for its raw wilderness is an evidence to the character of two cultures:the explorers who braved its hardships and the Native Americans who prize and conserve the path as a sacred (神圣的)gift. It remains today the same condition as when Lewis and Clark walked it.

    The Lolo is passable only from July to mid-September. Our luck is holding with the weather, although the snow keeps getting deeper. As we climb to Indian Post Office, the highest point on the trail at 7,033 ft, we have covered 13 miles in soft snow, and we hardly have enough energy to make dinner. After a meal of chicken, I sit on a rock on top of the ridge .There is no light visible in any direction, not even another campfire. For four days we do not see another human being. We are occupied with the things that mix fear with joy. In our imagination we have finally caught up with Lewis and Clark.