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[Reading Comprehension]
试题详情
文章：
| Line | While the most abundant and dominant species |
| within a particular ecosystem is often crucial in | |
| perpetuating the ecosystem, a “keystone” species, | |
| here defined as one whose effects are much larger | |
| (5) | than would be predicted from its abundance, can |
| also play a vital role. But because complex species | |
| interactions may be involved, identifying a keystone | |
| species by removing the species and observing | |
| changes in the ecosystem is problematic. It might | |
| (10) | seem that certain traits would clearly define a species |
| as a keystone species; for example, | |
| Pisaster ochraceus is often a keystone predator | |
| because it consumes and suppresses mussel | |
| populations, which in the absence of this starfish | |
| (15) | can be a dominant species. But such predation on a |
| dominant or potentially dominant species occurs in | |
| systems that do as well as in systems that do not | |
| have species that play keystone roles. Moreover, | |
| whereas P. ochraceus occupies an unambiguous | |
| (20) | keystone role on wave-exposed rocky headlands, |
| in more wave-sheltered habitats the impact of | |
| P. ochraceus predation is weak or nonexistent, | |
| and at certain sites sand burial is responsible for | |
| eliminating mussels. Keystone status appears to | |
| (25) | depend on context, whether of particular |
| geography or of such factors as community | |
| diversity (for example, a reduction in species | |
| diversity may thrust more of the remaining species | |
| into keystone roles) and length of species | |
| (30) | interaction (since newly arrived species in particular |
| may dramatically affect ecosystems). |
题目：
The passage suggests which of the following about the identification of a species as a keystone species?
选项:
A、Such an identification depends primarily on the species’ relationship to the dominant species.
B、Such an identification can best be made by removing the species from a particular ecosystem and observing changes that occur in the ecosystem.
C、Such an identification is likely to be less reliable as an ecosystem becomes less diverse.
D、Such an identification seems to depend on various factors within the ecosystem.
E、Such an identification can best be made by observing predation behavior.
答案:
D
提问：
请问这题B错在了哪里，是错在best这里吗？
解答：
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提问：
请问这题B错在了哪里，是错在best这里吗？
解答：
点赞0
阅读946
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