Many people are surprised to learn that Antarctica is nearly twice the size of the United States. The name Antarctica was coined

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问题     Many people are surprised to learn that Antarctica is nearly twice the size of the United States. The name Antarctica was coined to mean "opposite to the Arctic. " It is just that in many ways. Antarctica is a high, ice-covered landmass. In the Arctic the landmasses are grouped around the ice-covered Arctic Ocean.
    Largely because of this difference, the climate of the two areas is very different. Antarctica is the coldest area in the world. On the average it is about 30 degrees colder than the Arctic. At the South Pole, nearly 10,000 feet high, monthly mean temperatures run well below zero. Only in coastal regions do temperatures sometimes rise above freezing in the summer(December to March). In contrast, near the North Pole monthly mean temperatures often rise above freezing.
    At both poles, daily temperatures may drop far below the monthly mean. At the American South Pole Station, winter temperatures sometimes fall below-100 degrees Fahrenheit. Elsewhere, on higher parts of the south polar plateau, even lower temperatures are recorded. A temperature of-127 degrees Fahrenheit was measured in August 1960. It is the world’s record low temperature.
    Partly because of this climatic difference, the land animals and plants of the two regions are very different. On the continent of Antarctica, there are very few plants. In the Arctic there are many plants. In some of the few ice-free areas of Antarctica, mosses, lichens, and algae are found. Penguins populate Antarctic coastlines but do not exist in the Arctic. The land animals of the Arctic are foxes, bears, reindeer, and lemmings. These animals are unknown in the Antarctic. Old rock layers show that this "oppositeness" between north and south extends far back into the early chapters of earth history.
    Ice is the great feature of Antarctica. More than 4. 5 million square miles of ice sheet cover the area. Great rivers of ice, called glaciers, push down the mountains. Antarctica is the storehouse of about 85 percent of the total world supply of ice.
    The icecap is very thick, averaging nearly 8,000 feet. At one spot, scientists have found the distance from the surface to the rock underneath the ice to be more than 13,000 feet.
    If this great volume of ice were to melt, the volume of the world oceans would increase, and sea level would rise, and there would be a threat to coastal areas. Extreme atmospheric changes would have to take place for this to happen.
The author develops his point through______.

选项 A、theory and proof
B、cause and effect
C、comparison and contrast
D、description and argumentation

答案C

解析
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