逻辑难题,一点头绪都没有

ambguy

GRE， GMAT， LSAT 逻辑推理 P110 (36)

There is a great deal of geographical variation in the frequency of many surgical procedures – up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.

To support a conclusion that much of the variation is due to unnecessary surgical procedures, it would be most important to establish which of the following?
(A) A local board of review at each hospital examines the records of every operation to determine whether the surgical procedure was necessary.
(B) The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered.
(C) There are several categories of surgical procedure (other than hysterectomies, prostatectomies, and tonsillectomies) that are often performed unnecessarily.
(D) For certain surgical procedures, it is difficult to determine after the operatin whether the procedures were necessary or whether alternative treatment would have succeeded.
(E) With respect to how often they are performed unnecessarily, hysterectomies, prostatectomies, and tonsillectomies are representative of surgical procedures in general.


GRE， GMAT， LSAT 逻辑推理 P114 (43)

Most geologists believe oil results from chemical transformations of hydrocarbons derived from organisms buried under ancient sea. Suppose, instead, that oil actually results from bacterial action on other complex hydrocarbons that are trapped within the earth. As is well known, the volume of these hydrocarbons exceeds that of buried organisms. Therefore, our oil reserved would be greater than most geologists believe.

Which of the following, if rue, gives the strongest support to the argument above about our oil reserves?
(A) Most geologists think optimistically about the Earth’s reserves of oil.
(B) Most geologists have performed accurate chemical analyses on previously discovered oil reserves.
(C) Ancient seas are buried within the Earth at many places where fossils are abundant.
(D) The only bacteria yet found in oil reserves could have leaked down drill holes from surface contaminants.
(E) Chemical transformations reduce the volume of buried hydrocarbons derived from organisms by roughly the same proportion as bacterial action reduces the volume of other complex hydrocarbons.

i am confused....


3.
The wild mouflon sheep of the island of Corsica are direct descendants of sheep that escaped from domestication on the island 8,000 years ago. They therefore provide archaeologists with a picture of what some early domesticated sheep looked like,before the deliberate selective breeding that produced mordern domesticated sheep began.

The argument above makes which of the following assumptions?
1.There are no other existing breeds of sheep that escaped from
domestication at about the same time as the forbears of the mouflon
2.Mouflon sheep are more similar to their for-bear of 8,000 years
ago than modern domesticated sheep are to theirs.

i choose 1. the answer is 2. why?

卧室春竹

1 我觉得....因为要support the variation is due to unnecessary surgical procedures  B选项 就是排除了他因了 说明 variation 就是因为 unnecessary surgical

2 A-石油 B-石油

A>B 就说明A产生的石油比B多吗？ 当然不一定 E选项说明了 AB在转化石油的过程中损耗一样  所以是正确答案

3 我觉得 1选项 无关紧要啊！~  无所谓有没有other existing breed of sheep