问题详情

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As the volcano erupts in Iceland, more and more people are beginning to concern about the damage volcanic eruption brings. Then, let us learn the influence of volcanic eruption together.
We all know that air pollution has an effect on the world"s average air temperature. Scientists declare that volcanic eruption leads to weather changes, which is similar to air pollution. How will volcanic eruption impact on weather？ Volcanic eruption throws hundreds of millions tons of ash into the stratosphere. The ash from a volcano spreads in a few days. However, this is not the end. The ash will remain in the air for years. Hereby, all the ash turns incoming solar radiation into space, which cools the earth.
The eruption would affect every level of ecosystem, from worms to primates. The problem is not only the physical destruction of habitat, but also the sulfur gases over the area. The volcanic eruption makes many people homeless who have to search for food and residence everywhere. The movement of the population and refugees may lead to some instability in the region. They may become one part to damage the environment in face of starvation threat. If the lava pours into lakes, the water will be severely contaminated. The unusual accumulation of carbon dioxide in the lower strata of lake"s basin may even cause explosions.
The volcanic eruption is a huge disaster for human beings. It will cause massive dislocation in the local place. The Iceland volcano is a good example. More than 63,000 flights had been canceled in 23 European countries, which is severe blow on the economy. Travelers had to give up their joumeys. Fresh foods get decayed because of delayed transportation. The factories are not able to operate for lack of machinery parts. In other parts of the world, people canceled their flights to and from Europe, according to the Air Transport Association(ATA). This condition has an awful influence on the world economy.
Large quantities of dust and gaseous material. will be injected into the upper atmosphere as a re- sult of explosive eruptions. The volcano spurts a kind of glassy material with sharp edges, which is cooled by tiny shards of molten rock. The air is mixed with such material at a microscopic level.As a result, it will contribute to a worldwide rise in deaths of respiratory diseases.
51. From the second paragraph we learn that__________
[ A] Pollution causes a drop in the world"s average air temperature.
[B] Solar radiation will causes a drop in the air temperature.
[C] The ash of volcanic eruption will last for a long time.
[D] The ash in the stratosphere has no direct influence on people on land.请帮忙给出正确答案和分析，谢谢！