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OFFICIAL39 Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in summary because the express ideas that are not presented in the passage or are minor ideas in the passage. The Question is worth 2 points. Moa were large, flightless birds of New Zealand that became extinct several centuries ago. Drag your answer choices to the space where they belong. To remove an answer choice, double click on it.

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The Extinction of Moa
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Between 80 and 85 million years ago, Gondwanaland, a giant continent made up of what today is Africa, Antarctica, Australia, and South America, broke up, thus causing what is now New Zealand to become separated from the larger landmass. After the separation, any creature unable to cross a considerable distance of ocean could not migrate to New Zealand. Snakes and most mammals evolved after the separation. Thus there are no New Zealand snakes, and bats, which flew there, and seals, which swam there, were the only mammals on New Zealand when Polynesian settlers (the Maori) arrived there about a thousand years ago.

When the Maori arrived in New Zealand, they encountered birds that had been evolving for 80 million years without the presence of mammalian predators. The most striking of these animals must have been moa. Now extinct, moa were gigantic wingless birds that stood as much as 10 feet (3 meters) tall and weighed as much as 550 pounds (250 kilograms). They are known from a diverse array of remains including eggshells, eggs, a few mummified carcasses, vast numbers of bones, and some older fossilized bone. The species of moa that are currently recognized occupied ecological niches customarily filled elsewhere by large mammalian browsing herbivores. They may have had relatively low reproductive rates; apparently, they usually laid only one egg at a time.

It seems possible that when Captain James Cook first visited New Zealand in 1769, moa (or at least one of the moa species) may have still survived in the remote areas in the western part of New Zealand's South Island. If so, these individuals would have been the last of their kind. Climatic conditions in New Zealand appear to have been relatively stable over the period during which moa became extinct. Different factors could have worked in concert to account for their abrupt disappearance.

Vegetation was considerably altered by the Maori occupation of New Zealand, a change not easily explained by climate variation or other possible factors. Forest and shrubland burning appears to have reduced the prime habitat of many moa species. However, the main forest burning started around 700 years ago, after what current archaeological evidence indicates was the most intensive stage of moa hunting. While there appears to have been extensive burning on the east side of New Zealand's South Island, large forest tracts remained in the most southern part of the island. Because major habitat destruction seems to have occurred after moa populations already were depleted, and because some habitat that could have sheltered moa populations remained, it would seem that other factors were also at work in the extinction of these birds.

For South Island, human predation appears to have been a significant factor in the depletion of the population of moa. At one excavated Maori site, moa remains filled six railway cars. The density of Maori settlements and artifacts increased substantially at the time of the most intensive moa hunting (900 to 600 years ago). This period was followed by a time of decline in the Maori population and a societal transition to smaller, less numerous settlements. The apparent decline fits the pattern expected as a consequence of the Maori's overexploitation of moa.

Finally, the Maori introduced the Polynesian rat and the dog to New Zealand. The actions of these potential nest predators could have reduced moa populations without leaving much direct evidence. The Maori may have also inadvertently brought pests and disease organisms in fowls, which could have crossed over to eradicate moa populations. The possibility of analyzing ancient DNA to identify past diseases of extinct animals is being explored. However, evidence of such diseases is difficult to determine directly from paleoecological or archaeological remains. For these reasons, it is hard to determine the likelihood that introduced disease organisms were a cause of the decline of moa, but they are potentially significant.

While the last of these possible causes remains speculative, define clues exist for the action of the first two causes. The story of moa species and their demise raises ecological issues on the vulnerability of species to human-caused changes - including altered vegetative cover of the landscape, change in the physical environment, and modification of the flora and fauna of a region by eliminating some species and introducing others.

14.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in summary because the express ideas that are not presented in the passage or are minor ideas in the passage. The Question is worth 2 points. Moa were large, flightless birds of New Zealand that became extinct several centuries ago. Drag your answer choices to the space where they belong. To remove an answer choice, double click on it.

A.Because New Zealand had no large mammals, moa had no mammalian predators and occupied the ecological niches that elsewhere were occupied by large mammalian herbivores.

B.DNA analysis of moa remains revealed that the extinction of moa species occurred less than three centuries ago.

C.Scientists claim that forest burning is the factor most responsible for the disappearance of moa.

D.Initially, moa had a high reproductive rate, but overtime it significantly declined, largely due to changes in New Zealand's climatic pattern.

E.The extinction of moa was primarily caused by the hunting and deforestation activities of the Maori, who arrived in New Zealand about one thousand years ago.

F.The Maori introduced dogs, rats, and perhaps disease organisms, which may have contributed to the extinction of moa, but evidence is not available.

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正确答案:AEF
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【题目翻译】说明:下面提供了一个引言,简要总结一下这段话。通过选择三个回答选项来完成总结,这些选项表达了文章中最重要的观点。有些答案选择不属于总结性的,因为表达的观点没有出现在文章中,或者是文章中的次要观点。这个问题值2分。恐鸟是新西兰的大型的、不会飞的鸟类,几个世纪前就灭绝了。 A:由于新西兰没有大型哺乳动物,恐鸟没有哺乳动物捕食者,占据了其他地方被大型哺乳动物食草动物占据的生态位。 B:对恐鸟遗迹的DNA分析显示,恐鸟物种的灭绝发生在不到三个世纪前。 C:科学家声称森林燃烧是导致恐鸟消失的最主要因素。 D:最初,恐鸟的繁殖率很高,但随着时间的推移,繁殖率明显下降,主要是由于新西兰气候模式的变化。 E:恐鸟的灭绝主要是由于1000年前到达新西兰的毛利人的狩猎和森林砍伐活动造成的。 F:毛利人引进了狗、老鼠,也许还有疾病生物,这可能是导致恐鸟灭绝的原因,但是没有证据。 【判定题型】:根据问题的提问方式和6选3的作答方式可以确定该题目为概要小结题。 【选项定位及分析】 选项A说恐鸟没有哺乳动物的捕食者,并且占据了大型食草哺乳动物的生态位,概括了第二段内容,正确; 选项B文中没有对应的原文依据,错误; 选项C的意思是森林大火最应该为恐鸟灭绝负责,但是在第四段However后面的原文则说明了大火并不是主要原因,错误; 选项D说恐鸟灭绝是很大程度上因为气候改变,根据第三段倒数第一二句我们知道,气候在恐鸟灭绝的时候一直稳定,所以本选项错误; 选项E的意思是恐鸟因为毛利人的大量捕杀灭绝,概括了第四五段内容,正确; 选项F是说毛利人引入的老鼠,狗和疾病导致恐鸟灭绝,概括第六段内容,正确。 综合起来本题选择A,E,F。

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