2017年5-6月GMAT逻辑机经（6.11）（四）.

　　考古 from nowwsy

　　V1 from qq309790244

　　kill whale：seaotter数量减少。report说sealion 和seal也下降，killwhale吃sealion和seal，但是报告说killwhale吃seaotter is rare，但在1980前根本没有报告。所以seaotter下降是由于killwhale。问支持

　　Babee2queen: Sea otter在六月机经里出现过加强的版本：

　　C)seals and sea lions的食物大量减少，但是sea otters的prey没有减少(正确答案)

　　e) 在kill whale到不了的bay的sea otters数量和kill whale到的了的数量都减少了。

　　GWD原题：

　　In the late 1980’s, the population of sea otters in the North Pacific Ocean began to decline. Of the two plausible explanations for the decline—increased predation by killer whales or disease—disease is the more likely. After all, a concurrent sharp decline in the populations of seals and sea lions was almost certainly caused by a pollution-related disease, which could have spread to sea otters, whereas the population of killer whales did not change noticeably.

　　Which of the following, if true, most seriously weakens the reasoning?

　　A.Killer whales in the North Pacific usually prey on seals and sea lions but will, when this food source is scarce, seek out other prey.

　　B.There is no indication that substantial numbers of sea otters migrated to other locations from the North Pacific in the 1980’s.

　　C.Along the Pacific coast of North America in the 1980’s, sea otters were absent from many locations where they had been relatively common in former times.

　　D.Following the decline in the population of the sea otters, there was an increase in the population of sea urchins, which are sea otters’ main food source.

　　E.The North Pacific populations of seals and sea lions cover a wider geographic area than does the population of sea otters.

　　13、船速与鱼 GWD变体

　　V1 from ffffighting

　　变体2. 某种鱼类数量decline，是因为船速太快，容易与相撞。当地已有相关规定船只应减速，措施有效，因为鱼数量increase。问evaluation

　　只记得一个选项：Whether那些被撞的鱼正在mature的年龄。完全忘了选什么了。

　　V2 from 20339886

　　还有鱼和船相撞的那题，题目结论说限速可以达到预期建立在哪个假设之上?我选的是这些渔船不会绕道走别的不限速的水域

　　V3 from xinxinokkk 650

　　在某地鱼因为和船相撞数量减少，所以出台限速令那题，应该是变体，因为后面说限速令出台后鱼数量增加，所以限速令是有效的。

　　问Ealuate(GWD应该没有说数量增多，而且是问的Assumption吧?)

　　我选的是是否有船因为限速令而转到别的航线了?

　　主人原话：对就是这个的题干，细节有变动，选项基本改掉了

　　GWd：

　　Manatees, aquatic mammals inhabiting Florida’s rivers and coastal waters, swim close to the surface and are frequently killed in collisions with boats. To address the problem, boat traffic in manatee-populated waters is being required to maintain very low speeds. Unfortunately, manatees are unable to hear low-pitched sounds and a boat’s sound lowers in pitch as the boat slows. Therore, this approach may in fact make things worse rather than better.

　　Which of the following, if true, casts most doubt on the conclusion?

　　A.The areas where boats would have to maintain low speeds were decided partly on the basis of manatee-population estimates and partly from numbers of reported collisions between manatees and boats.

　　B.Because the water hyacinth that manatees feed on grows best in water that is nearly still, water hyacinth beds can be disturbed or damaged by fast-moving boat traffic.

　　C.Over the last several decades, boat traffic in Florida’s coastal waters has been increasing almost continuously and now represents the greatest threat to the endangered manatee population.

　　D.The sound of a boat engine generally travels much further under water than it does through the air.

　　E.When experimenters exposed manatees to the recorded sounds of boats moving at various speeds, the creatures were unable to discern the sounds over normal background noise.

　　14、监狱program

　　V1 from ffffighting

　　某监狱里有个program，貌似包括一些娱乐等措施(?不确定)。说这个program不好，因为入狱的人变多了。问解释或加强(真的记不请了)

　　我选的是最有喜感的选项：入狱waiting list的人争着要加这个program。

　　V2 from Winnelxx 600

　　考了监狱那道：就是监狱人数增加的原因， 问削弱的那个狗狗

　　15、孕妇实验

　　V1 from damei12

　　一实验分两组，一组孕妇怀孕的时候吃维他命，生出来的BB更健康，另外一组， 没发现这个规律，解释paradox的原因