reproduction
reproduction
相关考题：
Passage ThreeQuestions 31 to 35 are based on the following passage.An understanding of man's effect on the balance of nature is crucial (关键的) to being able to find the appropriate remedial action. It is a very common belief that the problems of the population explosion are caused mainly by poor people living in poor countries who do not know enough to limit their reproduction. This is not true. The actual number of people in an area is not as important as the effect they have on nature. Developing countries do have an effect on their environment, but it is the populations of richer countries that have a far greater impact on the earth as a whole.For example, tropical forests are known to be essential to the balance of nature, yet we are destroying them at a great rate. They are being cleared not to benefit the natives of that country, but to satisfy the needs of rich countries. Central American forests are being destroyed for grassland to make pet food in the United States cheaper; in Papua slew Guinea, forests are destroyed to supply cheaper cardboard packaging for Japanese electronic products; in Burma and Thailand, forests have been destroyed to produce more attractive furniture in Singapore and Hong Kong. Therefore, a rich person living thousands of miles away may cause more tropical forest destruction than a poor person living in the forest itself.In short, it is everybody's duty to safeguard the future of mankind—not only through population control, but by being more aware of the effect his actions have on nature. Nature is both fragile and powerful. It is very easily destroyed; on the other hand, it can easily destroy its most dangerous enemy—man.31.According to the first paragraph, people usually believe that .A.poor people in poor countries contribute to the imbalance of natureB. rich people know how to protect the environment by taking actionsC. people in poor areas know a lot about the birth controlD. rich people in rich countries have done a lot to balance nature
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共用题干Malnutrition"Much of the sickness and death attributed to the major communicable diseases is in fact caused by malnutrition which makes the body less able to withstand infections when they strike",said Dr.Hiroshi Na-kajima,Director-General of the World Health Organization(WHO),in his statement on the first day of theWorld Food Summit organized by the Food and Agriculture Organization of the United Nations in Rome,Italy,from 1 3 to 17 November,1996."At the same time,"he added,"in developing countries today,malnutrition is the cause of 174 million children under five years of age being underweight,and 230 million being stunted in their growth.Such figures represent deprivation, suffering and wasted human potential on a scale that is unacceptable from every point of view.Whether we think in terms of humanitarian concern,common justice or development needs, they demand a response,both from national governments and from international community."At the end of January 1996,98 countries had national plans of action for nutrition and 41 countries had one under preparation,in keeping with their commitments made at the International Conference on Nutrition in Rome in December 1992.The global situation,however,remains grim.Over 800 million people around the world still cannot meet basic needs for energy and protein,more than 2 ,000 million people lack essential micronutrients,and hundreds of millions suffer from diseases caused by unsafe food and unbalanced diets.In sheer numbers,iron is the most prevalent micronutrient deficiency.Mainly women of reproduction' age and children under five are affected by iron deficiency with prevalence hovering around 50% in developing countries.Among various regions in the world,it is South Asia which is hit hardest with prevalence reaching 80% in some countries.Tn infants and young children even mild anemia is associated with impaired intellectual as well as physical development.In older children and adults iron deficiency reduces work capacity and output.It also leads to increased accidents at work.While there is no single remedy,a combination of several preventive approaches is believed to work best.Dietary improvement includes consumption of iron-and vitamin C-rich foods and foods of animal origin, and avoiding drinking tea or coffee with or soon after meals.Iron supplementation of foods,particularly of staple cereals,is practiced in a growing number of countries.Iron supplementation is the most common approach,particularly for pregnant women.How many countries have made plans of action for nutrition?A:98.B:41.C:139. D:57.
共用题干第三篇Save PandasWith the Switzerland-based World Wildlife Fund(WWF),China is making a concerted and dedicated effort to save the endangered pandas. The results,officials here in Chengdu indicate,are mixed but encouraging.A clear disappointment is the failure to breed pandas in captivity,necessary if their decreasing numbers are to be replaced.Another failure has been the incapability to find a natural,readily available food to replace the arrow bamboo.Despite these failures,success has come on two fronts.One achievement has been the physical rescue effort. Some pandas have been kept alive by salting（空投）the mountains with tons of cooked meat , which pandas will eat as a substitute for bamboo,and by the planting of new bamboo in isolated areas.Animals in some Sichuan areas have been rescued by local peasants and given emergency treatment by animal doctors.A second achievement is a massive fund-raising effort.Publicity about the pandas plight has resulted in a new$100,000 emergency allocation by the WWF and independent fund drives both in China and abroad.In spite of this support,there have been conflicts in the panda relief program.One important problem is the difficulty Peking is having balancing the recommendations of environmentalists with China's ambitious goal of agricultural and industrial modernization.Wolong is but one example of this difficulty.This 494,000-acre preserve was declared a protected area in 1975.Yet 1,800 people,mostly Tibetans,still live in the preserve,logging trucks still roll down the narrow mountain roads,and blasting work still goes on at the site of a new 160,000-kilowatt hydroelectric plant just six miles away.This all means that the pandas' fight for survival will not be an easy one,even with the concerted effort of man.For in the end,even if they can survive the dangers of the wild,they must still contend with man himself.All of the following help prevent the decline of the panda population EXCEPT_________.A:the reproduction of panda offspring during captivityB:the large-scale fund-drivesC:the rescue of the injured and the sickD:the cultivation of new bamboo forests
共用题干Save PandasWith the Switzerland-based World Wildlife Fund(WWF),China is making a concerted and dedicated effort to save the endangered pandas.The results,officials here in Chengdu indicate,are mixed but encouraging.A clear disappointment is the failure to breed pandas in captivity,necessary if their decreasing numbers are to be replaced.Another failure has been the incapability to find a natural,readily available food to replace the arrow bamboo. Despite these failures,success has come on two fronts.One achievement has been the physical rescue effort.Some pandas have been kept alive by salting（空投）the mountains with tons of cooked meat , which pandas will eat as a substitute for bamboo,and by the planting of new bamboo in isolated areas.Animals in some Sichuan areas have been rescued by local peasants and given emergency treatment by animal doctors.A second achievement is a massive fund-raising effort.Publicity about the pandas plight has resulted in a new$100,000 emergency allocation by the WWF and independent fund drives both in China and abroad.In spite of this support,there have been conflicts in the panda relief program.One important problem is the difficulty Peking is having balancing the recommendations of environmentalists with China's ambitious goal of agricultural and industrial modernization.Wolong is but one example of this difficulty.This 494,000-acre preserve was declared a protected area in 1975.Yet 1,800 people,mostly Tibetans,still live in the preserve,logging trucks still roll down the narrow mountain roads,and blasting work still goes on at the site of a new 160,000-kilowatt hydroelectric plant just six miles away.This all means that the pandas'fight for survival will not be an easy one,even with the concerted effort of man.For in the end,even if they can survive the dangers of the wild,they must still contend with man himseff.All of the following help prevent the decline of the panda population EXCEPT_____＿.A:the reproduction of panda offspring during captivityB:the large-scale fund-drivesC:the rescue of the injured and the sickD:the cultivation of new bamboo forests
共用题干Changes in MuseumsMuseums have changed.They are no longer places that one"should"visit;they are places to enjoy and learn.At a science museum in Ontario,Canada,you can feel your hair stand on end as harmless electricity passes through your body.At the Metropolitan（大城市的）Museum of Art in New York City , you can look at the seventeenth century instruments while listening to their music.At New York's American Museum of Natural History recently,you can help make a bone-by- bone reproduction of the museum's dinosaur（恐 龙）,a beast that lived 200 million years ago.More and more museum directors are realizing that people learn best when they can somehow become part of what they are seeing.In many science museums,for example,there are no guided tours.The visitor is encouraged to touch,listen,operate,and experiment so as to discover scientific principles for himself. The purpose is not only to provide fun but also to help people feel at home in the world of science.The theory is that people who do not understand science will probably fear it,and those who fear science will not use it to best advantage.One cause of all these changes is the increase in wealth and leisure time.Another cause is the rising percentage of young people in the population.Many of these young people are college students or college graduates.Leon F.Twiggs,a young black professor of art once said,"They see things in a new and different way.They are not satisfied to stand and look at works of art;they want art they can participate（参加）in."The same is true of science and history.In America today,all science museums are open to the public and free.A:Right B:WrongC:Not mentioned
Small in-ceiling speakers are BEST suited for（）A、loud， bass intensive music （e.g. heavy metal， rock）.B、providing a sub-woofer for great bass reproduction.C、background music and blending in with decor.D、the user who wants perfect sound reproduction.
单选题Which of the following is NOT mentioned as the result of artificial selection by humanity?AMany new kinds of plants and animals are produced.BFinancial gain is increased considerably by producing better plants and animals.CHumans are able to control plant and animal reproduction for humans’ pleasure.DIt is necessary for humans to maintain the artificial environments.
问答题Practice 1 After nearly a year of emotional arguments in Congress but no new federal laws the national debate over the future of human cloning has shifted to the states. Six states have already banned cloning in one form or another，and this year alone 38 anticloning measures were introduced in 22 states. The resulting patchwork of laws，people on all sides of the issue say，complicates a nationwide picture already clouded by scientific and ethnical questions over whether and how to restrict cloning or ban it altogether. Since l997，when scientists announced the birth of Dolly the sheep，the first cloned mammal，the specter of cloned babies, infants that ate，in essence，genetic carbon copies of adults has loomed large in the public psyche and in the minds of lawmakers. Today, there is widespread agreement that cloning fur reproduction is unsafe and should be banned. Now，the debate has shifted away from the ethics of baby-making and toward the morality of cloning embryos for their cells and tissues，which might be used to treat diseases. The controversy pits religious c6nservatives and abortion opponents, who regard embryos as nascent human life，against patients' groups，scientists and the biotechnology industry.
单选题Small in-ceiling speakers are BEST suited for（）Aloud， bass intensive music （e.g. heavy metal， rock）.Bproviding a sub-woofer for great bass reproduction.Cbackground music and blending in with decor.Dthe user who wants perfect sound reproduction.
问答题Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye. 1) It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions.New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce (differential reproduction). 2)It is possible for a genetic novelty (new variation) to spread in time to all members of a population, especially if the novelty enhances the population’s chances for survival in the environment in which it exists.Thus, when a species is introduced into a new habitat, it either adapts to the change by natural selection or by some other evolutionary mechanism or else it eventually dies off. Because each new habitat means new adaptations, habitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species. The total number of animal and plant species is estimated at between 2,000,000 and 4,500,000; authoritative estimates of the number of extinct species range from 15,000,000 up to 16,000,000,000. 3)Although the use of classification as a means of producing some kind of order out of this staggering number of different types of organisms appears as early as the book of Genesis—with references to cattle, beasts, fowl, creeping things, trees, etc.—the first scientific attempt at classification is attributed to the Greek philosopher Aristotle, who tried to establish a system that would indicate the relationship of all things to each other.He arranged everything along a scale, or “ladder of nature”, with nonliving things at the bottom; plants were placed below animals, and man was at the top. 4)Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. 5)At the present time taxonomy is based on two major assumptions: one is that similar body construction can be used as a criterion for a classification grouping; the other is that, in addition to structural similarities, evolutionary and molecular relationships between organisms can be used as a means for determining classification.