【正文】 however, its findings have been questioned, and similar studies on other ecosystems have not always found a positive relationship between diversity and stability. Clearly, this is a plex issue that requires further field research with a broad spectrum of ecosystems and species: grassland plants and puter models will only take us so far. In the end, despite insightful attempts to detect some general patterns, we may find it very difficult to reduce this topic to a simple, universal truth.1. The word significant in the passage is closest in meaning toO directO importantO longtermO surprising2. According to paragraph 1, why has the extinction of species been a concern for conservation biologists?O When ecosystems lose just one species, they undergo permanent change.O The extinction of a particular predator species could cause an overpopulation of certain prey species.O The loss of one or more species could cause the decline of a whole ecosystem.O The extinction of a single species is evidence that plantfood sources are in danger of disappearing.3. According to paragraph 1, what was the result of the removal of Pacific sea otters?O The kelp and sea urchins were destroyed by new predators.O The uncontrolled population of sea urchins ate most of the kelp plants.O Without sea otters, the kelp beds soon became overgrown.O Macroalgae remained as the primary population in the ecosystem.4. The word “redundancy” in the passage is closest in meaning toO duplicationO varietyO requirementsO flexibility5. What is the function of paragraph 2 in the passage?O To present a hypothesis about ecosystem diversity and some reasons why it might be trueO To give examples of types of ecosystems that have the greatest diversityO To contradict a previous belief about the stability of speciesrich ecosystemsO To contrast speciesrich and speciespoor ecosystems6. According to paragraph 2, which of the following increases the stability of anecosystem?O Species in which producers outnumber predatorsO New or exotic species that increase ecosystem diversityO Heavily populated species that are free of diseaseO Species that are diverse but have similar nutritional roles7. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.O In any ecosystem, as the number of individuals in the same species increases, the rate of disease transmission slows down.O Ecosystems that have a small number of different species tend to be diseasefree, because the species’ habitats are at a safe distance from each other.O In ecosystems with many species, diseases spread more slowly because there are fewer individuals in a species and, as a result, the individuals are more widely scattered.O The average distance between individuals in a speciesrich ecosystem increases, so diseases are prevented from being municated between species.8. The phrase ”pensating for in the passage Is closest in meaning toO working againstO leaving outO making up forO spreading over9. What Is the main importance of the study discussed in paragraph 3?O It examines the response of certain grassland plants to a drought.O It contains an index of plants that survived well in times of drought.O It provides scientific evidence that diversity helps to make ecosystems stable.O It shows that ecosystems contain both resistant species and less tolerant ones.10. Select the TWO answer choices that, according to paragraph 4, are conclusions that can be drawn from the study by Tilman and Downing. To receive credit you must select TWO answer choices.□ A diverse ecosystem will have species that respond differently to a variety of conditions.□ Species within a speciesrich ecosystem are more likely to have petitors.□ An ecosystem is more likely to develop diverse and stable species when it is exposed to extreme conditions.□ Species with similar ecological functions will perform the function of a lost species.11. The word “detect” in the passage is closest in meaning toO repeatO alterO findO emphasize12. According to paragraph 5, which of the following is true about Tilman and Downing’s findings?O General patterns of diversity and stability have been established as a result of the findings.O Questions about the findings have been refuted by puter models.O The findings have been tested in a broad spectrum of ecosystems with similar results.O The findings are not sufficient to prove a definite link between diversity and stability in ecosystems.13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.It seems clear that there is room for a great deal more research, although some work has been done.Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Drag your answer choices to the spaces where they belong To remove an answer choice, click on itTo review the passage, click VIEW TEXTBiologists have long been worried about the possible effect of the extinction of species on whole ecosystems.Answer ChoicesConservation biology studies Indicate that the loss of a single important species may bring temporary change to an ecosystem but it seldom results in lasting damage.Ecosystems having species with similar functions but different responses to adverse conditions can survive environmental disturbances.The Minnesota grassland study by Tilman an