Tiger beetles are suchfast runners that they can capture virtually any nonflying insect. However, when running toward an insect, thebeetles intermittently stop, and then, a moment later, resume theirattack. erhaps they cannot maintaintheir pace and must pause for a moment's rest; but an alternative hypothesis isthat while running tiger beetles are unable to process the resulting rapidlychanging visual information, and so quickly go blind and stop.
Which of thefollowing, if discovered in experiments using artificially moved prey insects,would support one of the two hypotheses and undermine the other?
(A) When a prey insectis moved directly toward a beetle that has been chasing it, the beetleimmediately turns and runs away without its usual intermittent stopping.
(B) In pursuing amoving insect, the beetles usually respond immediately to changes in theinsect's direction, and pause equally frequently whether the chase is up ordown an incline.
(C) The beetlesmaintain a fixed time interval between pauses, although when an insect that hadbeen stationary begins to flee, the beetle increases its speed after its nextpause.
(D) If, when a beetlepauses, it has not gained on the insect it is pursuing, the beetle generallyends its pursuit.
(E) When an obstacleis suddenly introduced just in front of running beetles, the beetles sometimesstop immediately, but they never respond by running around the barrier.
答案C
提问:
为什么不是E
(1)C中提到beetle会有停顿(和题干中一样),beetle追一个从静止突然逃跑的虫会加速。并没有和原来的情况有什么不一样。为什么对?
(2)E中,面对突然加入的障碍物,奔跑中的beetle:会立刻stop,说明视力好(反对); 不会绕开障碍物,说明步伐调不过来确实不行(支持)。这个选项应该对。
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