博智教育 GMAT培训 GMAT每日一题
In order to withstand tidal currents, juvenile horseshoe crabs frequently burrow in the sand. Such burrowing discourages barnacles from clinging to their shells. When fully grown, however, the crabs can readily withstand tidal currents without burrowing, and thus they acquire substantial populations of barnacles. Surprisingly, in areas where tidal currents are very weak, juvenile horseshoe crabs are found not to have significant barnacle populations, even though they seldom burrow.
Which of the following, if true, most helps to explain the surprising finding?
(A) Tidal currents do not themselves dislodge barnacles from the shells of horseshoe crabs.
(B) Barnacles most readily attach themselves to horseshoe crabs in areas where tidal currents are weakest.
(C) The strength of the tidal currents in a given location varies widely over the course of a day.
(D) A very large barnacle population can significantly decrease the ability of a horseshoe crab to find food.
(E) Until they are fully grown, horseshoe crabs shed their shells and grow new ones several times a year.
题目分析：问现象解释原文一定存在一个矛盾点，我问的就是明明我不挖坑了但是barnacle的数量也没有增长，这是为什么。A说因为current不会自己把barnacles从shells上冲下来，那barnacles不会冲下来数量就会多啊，怎么反而少了呢？不符合问题要求，杀。B说barnacles通常会在current最弱的时候把自己吸附在horseshoe上，都吸附上了，怎么数量还少了，还是不符合问题要求，杀。C说current的强弱在一天内变化幅度较大，没说，杀。D说barnacle数量多会降低horseshoe觅食的能力，扯得更远了，杀。E说horseshoe经常长新壳，所以在新壳上没有太多的barnacles，这个理由说得通，留着。
博智教育 GMAT培训 GMAT每日一题
