对原尿中的全部葡萄糖、大部分水和部分无机盐有重吸收作用的是（ ）
A．肾动脉
B．肾小球
C．肾小囊
D．肾小管
答案：D
题目分析：当血液流经肾小球时，除了血细胞和大分子的蛋白质外，其他的如水、无机盐、尿素、葡萄糖会滤过到肾小囊腔形成原尿；当原尿流经肾小管时，其中大部分水、部分无机盐和全部的葡萄糖被重新吸收回血液，而剩下的如尿素、一部分无机盐和水构成了尿液的成分．所以，对原尿中的全部葡萄糖、大部分水和部分无机盐有重吸收作用的是肾小管．
故选：D．
Passage Two
| Conventional wisdom has it that concern for the environment is a luxury only the rich world can afford; that only people whose basic needs for food and shelter have been met can start worrying about the health of the planet. This survey will argue that developing countries, too, should be thinking about the environment. True, in the rich countries a p environmental movement did not emerge until long after they had become industrialized, a stage that many developing countries have yet to reach. And true, many of the developed world’s environmental concerns have little to do with immediate threats to its inhabitants’ well-being. People worry about whether carbon-dioxide emissions might lead to a warmer climate next century, or whether genetically engineered crops might have unforeseen consequences for the ecosystem. That is why, when rich world environmentalists’ campaign against pollution in poor countries, they are often accused of naivety. Such countries, the critics say, have more pressing concerns, such as getting their people out of poverty. But the environmental problems that developing countries should worry about are different from those that western pundits have fashionable arguments over. They are not about potential problems in the next century, but about indisputable harm being caused today by, above all, contaminated water and polluted air. The survey will argue that, contrary to conventional wisdom, solving such problems need not hurt economic growth; indeed dealing with them now will generally be cheaper than leaving them to cause further harm. In most developing countries pollution seems to be getting worse, not better. Most big cities in Latin America, for example, are suffering rising levels of air pollution. Populations in these countries are growing so fast that improvements in water supply have failed to keep up with the number of extra people. Worldwide, about a billion people still have no access to clean water, and water contaminated by sewage is estimated to kill some 2 million children every year. Throughout Latin America, Asia, Africa, forests are disappearing, causing not just long-term concern about climate change but also immediate economic damage. Forest fires in Indonesia in 1997 produced a huge blanket of smog that enveloped much of South-East Asia and kept the tourists away. It could happen again, and probably will. Recent research suggests that pollution in developing countries is far more than a minor irritation: it imposes a heavy economic cost. A World Bank study put the cost of air and water pollution in China at $ 54 billion a year, equivalent to an astonishing 8% of the country’s GDP. Another study estimated the health costs of air pollution in Jakarta and Bangkok in the early 1990s at around 10% of these cities’ income. These are no more than educated guesses, but whichever way the sums are done, the cost is not negligible. |
The passage is written for the purpose of ______.
A．analyzing the difference between the environmental problems in rich and poor countries
B．arguing why developing countries should take immediate action to deal with their environmental problems
C．demonstrating how serious damage pollution can cause to a country’s economic development
D．explaining why the developed world’s environmental concerns have little to do with immediate threats