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[Reading Comprehension]
试题详情
文章：
| Line | Biologists have advanced two theories to explain |
| why schooling of fish occurs in so many fish species. | |
| Because schooling is particularly widespread among | |
| species of small fish, both theories assume that | |
| (5) | schooling offers the advantage of some protection |
| from predators. | |
| Proponents of theory A dispute the assumption | |
| that a school of thousands of fish is highly visible. | |
| Experiments have shown that any fish can be seen, | |
| (10) | even in very clear water, only within a sphere of 200 |
| meters in diameter. When fish are in a compact group, | |
| the spheres of visibility overlap. Thus the chance of | |
| a predator finding the school is only slightly greater | |
| than the chance of the predator finding a single fish | |
| (15) | swimming alone. Schooling is advantageous to the |
| individual fish because a predator’s chance of finding | |
| any particular fish swimming in the school is much | |
| smaller than its chance of finding at least one of | |
| the same group of fish if the fish were dispersed | |
| (20) | throughout an area. |
| However, critics of theory A point out that some | |
| fish form schools even in areas where predators | |
| are abundant and thus little possibility of escaping | |
| detection exists. They argue that the school continues | |
| (25) | to be of value to its members even after detection. |
| They advocate theory B, the “confusion effect,” which | |
| can be explained in two different ways. | |
| Sometimes, proponents argue, predators simply | |
| cannot decide which fish to attack. This indecision | |
| (30) | supposedly results from a predator’s preference |
| for striking prey that is distinct from the rest of the | |
| school in appearance. In many schools the fish are | |
| almost identical in appearance, making it difficult for a | |
| predator to select one. The second explanation for | |
| (35) | the “confusion effect” has to do with the sensory |
| confusion caused by a large number of prey moving | |
| around the predator. Even if the predator | |
| makes the decision to attack a particular fish, | |
| the movement of other prey in the school can | |
| (40) | be distracting. The predator’s difficulty can |
| be compared to that of a tennis player trying | |
| to hit a tennis ball when two are approaching | |
| simultaneously. |
题目：
The author is primarily concerned with
选项:
A、discussing different theories
B、analyzing different techniques
C、defending two hypotheses
D、refuting established beliefs
E、revealing new evidence
答案:
A
提问：
我看着第三段however反驳了A的理论就选了D
解答：
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阅读578
提问：
我看着第三段however反驳了A的理论就选了D
解答：
点赞0
阅读579
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