LSAT-2-4-8 偶觉得没有正确答案：（[求助]

G-CRACKER

LSAT-T2-SECTION IV-8 ，看了很久觉得没有答案。。。参考答案是C, 可是从文中根本找不出，CLIMATE FLUCTUATION 与 DATING ACCURACY之间的联系。。。。：（

8. Measurements of the extent of amino-acid decomposition in fragments of eggshell found at archaeological sites in such places as southern Africa can be used to obtain accurate dates for sites up to 200,000 years old. Because the decomposition is slower in cool climates, the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions.

The information above provides the most support for which one of the following conclusions?

(A) The oldest archaeological sites are not in southern Africa, but rather in cooler regions of the world.

(B) The amino-acid decomposition that enables eggshells to be used in dating does not take place in other organic matter found at ancient archaeological sites.

(C) If the site being dated had been subject to large unsuspected climatic fluctuations during the time the eggshell has been at the site, application of the technique is less likely to yield accurate results.

(D) After 200,000 ears in a cool climate, less than one-fifth of the amino acids in a fragment of eggshell that would provide material for dating with the technique will have decomposed and will thus no longer be suitable for examination by the technique.

(E) Fragments of eggshell are more likely to be found at ancient archaeological sites in warm regions of the world than at such sites in cooler regions.

smallkiddy

文章的前提是：蛋壳中的氨基酸在寒冷的环境中分解更慢

得出的结论是：在寒冷地区的蛋壳可以推测更古老的时代

这里有一个假设：按照不同温度，分解速度是恒定的，从而推出年代

C说：这个地方的温度经常变化，这样的话，分解速度就不是恒定的，这样推测出的年代结果就不够准确

lawyer_1

这是支持选项题。

the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions. 从该句可知分解速度和温度密切相关，测量精确性也依赖温度的相对稳定。反过来说，如果温度不能相对稳定，则测量精确性达不到。即C

smallkiddy

以下是引用lawyer_1在2004-10-14 9:39:00的发言：

这是支持选项题。

the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions. 从该句可知分解速度和温度密切相关，测量精确性也依赖温度的相对稳定。反过来说，如果温度不能相对稳定，则测量精确性达不到。即C

这类推论题目是不是针对文中的一个assumption进行推理呢？

G-CRACKER

以下是引用lawyer_1在2004-10-14 9:39:00的发言：

这是支持选项题。

the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions. 从该句可知分解速度和温度密切相关，测量精确性也依赖温度的相对稳定。反过来说，如果温度不能相对稳定，则测量精确性达不到。即C

这种assumption 合情理，但从原文并不能完全推出。文中两次提到accurate，一次是200000年的SITE, 一次是1000000年的SITE, 都是accurate的，并不存在 less or more accruate 的比较.........

Measurements  can be used to obtain accurate dates for sites up to 200,000 years old.  

the technique can be used to obtain accurate dates for sites almost a million years old in cooler regions.

smallkiddy

这两句话，都表明了在特定温度下的推理亚

lawyer_1

"并不存在 less or more accruate 的比较........." 问得好。

原文第一句话告诉我们用AMINO酸的分解程度去ACCURATE计算时间（分解程度和时间有对应关系）。第二句话告诉我们温度越低，分解越慢，故此可ACCURATE测量更早的时间（分解程度和温度有对应关系）。也就是说温度和可测量的时间有对应关系。低温对应可以测量时间多，年代老。高温则反之。如果是忽低忽高呢。显然这种对应关系受影响。是可能性变小。C说的是LESS LIKELY。

Bensontuo

G-CRACKER 发表于 2004-10-14 12:47
以下是引用lawyer_1在2004-10-14 9:39:00的发言：这是支持选项题。the technique can be used to obtain ac ...

Spot the question type: Must be true

Core of the argument:

M of Acd in foe ---> obtain accurate dates for sites up to 200,000 years old ---> decompositions is " slower " in cool climate ---> so, M for miilion years old in cooler regions ---> Obtain accurate.

what is the necessary assumptions ?

1. There must not be any variables to interfere the temps of cool climate.


let us dive into the answers.

A. Not really relevant to the argument, argument seeks to determine the validity of a technique could be accurate due to " temps of cool weather "

B. It is also not relevant to the argument, as long as nothing could change the decomposition rate under the indicated temps, it is could be true or could be wrong answer.

C. It does seems like a mistaken negate answer ( If A ---> B, you can't never say If No A ---> No B ), but it is truly relevant to the core of the argument. So, let us put it inside the contender.

D. Not necessary true. there is no any evidence indicating the exact amount needed to determine the accuracy of the measurement.

E. It is weaken answer.