To test the （ ）of borrowing from one field of study to enrich another, simply investigate the extent to which terms from the one may, without forcing, be utilized by the other.
The recent debate on acid rain is again setting environmentalist head to head against industry. But this time, a curious philosophy has emerged in Washington that says the more we know about a problem, the more uncertainty is introduced and the more it needs to be studied. As a result, we know more about acid rain and its effects, than ever before, but it seems a regulatory solution has never been further away.Researchers generally agree that acid rain arises primarily from the burning of coal and oil. The emissions contain oxides of nitrogen and sulfur, which can be carried hundreds of miles on the prevailing westerly winds. They eventually return to earth as dry gases and particulates and react with ground waters to form nitric or sulfuric acid. They may also be converted to the acids in the atmosphere by chemical processes that are still not fully understood.However, the acids are formed, they have already been charged with a substantial list of damages. Corrosion of metal structures in windward areas of the country has been well- documented, but it is a relatively minor entry on the list. Other forms of damage are far more insidious and longer-lasting. There is evidence, for example, that the acids leach heavy metals —aluminum, lead, and mercury — from the soil, which then poison plant roots and deprive them of vital nutrients. In lakes and rivers, the acid alters the blood chemistry in fish. The metals, meanwhile, irreversibly damage the gill systems of certain species, such as bass and walleye. As the concentration of poison rises, egg hatching is reduced and the number of deformed embryos increases.The effects of acid rain are more severe in the eastern part of the country for two reasons. First, most coal burning occurs in Ohio, Illinois, and Indiana, according to Eville Gorham, professor of ecology and botany at the University of Minnesota and a modern pioneer in the study of acid rain. These states produce about a quarter of all U.S. oxide emissions, he told this year’s American Chemical Society meeting in Las Vegas and the airborne particulates tend to wind up in the Northeast.The second reason is the varying chemical makeup of North American soils, Western soils are relatively rich in neutralizing compounds like magnesium and calcium carbonates, but the coarse, shallow eastern soils have much less of this buffering capacity. Together, these factors explain what Gorham calls a “pool of acid air pollution” over the Northeast that is strongly suspected of having killed or injured aquatic life in more than 200 lakes in New York’s Adirondack region.1.According to the passage, acid rain （ ）.2.The author implies that （ ）.3.The damaging effects of acid rain are felt less in the West because （ ）.4.The LEAST serious problem caused by acid rain is the（ ）.
The new biological psychiatry does not deny the contributing role of psychological factors in mental illnesses, but posits that these factors may act as a catalyst on existing physiological conditions and （ ）such illnesses.
All flights （ ）because of the snowstorm, many passengers could do nothing but take the train.
The electric fan does not work because of the （ ）of service.
Until about five years ago, the very idea that peptide hormones might be made anywhere in the brain besides the hypothalamus was astounding- Peptide hormones, scientists thought, were made by endocrine glands and the hypothalamus was thought to be the brains’ only endocrine gland. What is more, because peptide hormones cannot cross the blood-brain barrier; researchers believed that they never got to any part of the brain other than the hypothalamus, where they were simply produced and then released into the bloodstream.But these beliefs about peptide hormones were questioned as laboratory after laboratory found that antiserums to peptide hormones, when injected into the brain, bind in places other than the hypothalamus, indicating that either the hormones or substances that cross-react with the antiserums are present. The immunological method of detecting peptide hormones by means of antiserums, however, is imprecise. Cross-reactions are possible, and this method cannot determine whether the substances detected by the antiserums really are the hormones, or merely close relatives. Furthermore this method cannot be used to determine the location in the body where the detected substances are actually produced.New techniques of molecular biology, however, provide a way to answer these questions. It is possible to make specific complementary DNA’s (CDNA’s) that can serve as molecular probes to seek out the messenger RNA’s (mRNA’s) of the peptide hormones. If brain cells are making the hormones, the cells will contain these mRNA’s. If the products the brain cells make resemble the hormones but are not identical to them, then the cDNA’s should still bind to these mRNA’s, but should not bind as tightly as they would to mRNA’s for the true hormones. The cells containing these mRNA’s can then be isolated and their mRNA’s decoded to determine just what their protein products are and how closely the products resemble the true peptide hormones.The molecular approach to detecting peptide hormones using cDNA probes should also be much faster than the immunological method because it can take years of tedious purifications to isolate peptide hormones and then develop antiserums to them. Roberts, expressing the sentiment of many researchers, states: “I was trained as an endocrinologist. But it became clear to me that the field of endocrinology needed molecular biology input. The process of grinding out protein purifications is just too slow.”If, as the initial tests with cDNA probes suggest, peptide hormones really are made in the brain in areas other than the hypothalamus, a theory must be developed that explains their function in the brain. Some have suggested that the hormones are all growth regulators, but Rosen’s work on rat brains indicates that this cannot be true. A number of other researchers propose that they might be used for intercellular communication in the brain.1.Which of the following titles best summarizes the passage?2.The passage suggests that a substance detected in brain by use of antiserums to peptide hormones may（ ）. 3.The passage implies that, in doing research on rat brains, Rosen discovered that （ ）.4.Which of the following is a way in which the immunological method of detecting peptide hormones differs from the molecular method?