Cross-sections of stalactites - calcite formations deposited

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Scientist: Cross-sections of stalactites - calcite formations deposited on cave ceilings by seeping water - can reveal annual variations in rainfall in particular areas over hundreds and thousands of years. We often found that when-according to these cross-sections-drought occurred in a particular area, it coincided with the collapse of an ancient society in that area. I hypothesize that drought reduced agricultural productivity in these areas, thereby leaving these societies without the resources needed to handle internal stresses and external threats.

Which of the following, if true, would most weaken the support for the scientist's hypothesis?

A. Many droughts indicated in the cross-sections of stalactites do not correspond with the collapse of a society in that area.

B. Information from the cross-sections of stalactites alone cannot reveal the level of agricultural output in an area at a particular time.

C. Most of the societies that collapsed during droughts did so when internal power struggles coincided with military raids from neighboring societies.

D. Most of the societies that collapsed during droughts maintained large stockpiles of food and water at the time of their collapse.

E. Information from stalactites also suggests that the collapse of some societies coincided with periods of abnormally high rainfall.



OA is D

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by theperegrine » Tue Jul 05, 2016 7:43 am
The author of the argument is attributing causation to an evidence that merely suggests correlation. In order to weaken the argument you need to question the inference. Drought reduces productivity, alright, but does not necessarily cause collapse of the society. Look for a statement that best refutes this part of the argument.

A. Okay - but the rest of the droughts did correspond with the collapse of a society in that area. This statement does not reject the argument, but merely talks about another sample set.
B. This statement just rejects the evidence from stalactites - does not weaken the hypothesis that drought caused the collapse.
C. Just states that the power struggles coincided with the drought and the two reasons together caused the societal collapse. If anything, it adds to the hypothesis.
D. Refutes the argument that the loss of productivity caused societal collapse. If they maintained supplies, drought or even loss of productivity will not cause a collapse. Hence, this weakens the argument best and is the right answer.
E. Does not refute that drought caused the collapse.

Helps?