Critical Reasoning
Verbal Ability

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A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 trees to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora's extinction.

Which of the following, if true, most seriously weakens the argument above?


The drug made from ibora bark is dispensed to doctors from a central authority.


The drug made from ibora bark is expensive to produce.


The leaves of the ibora are used in a number of medical products.


The ibora can be propagated from cuttings and grown under cultivation.


The ibora generally grows in largely inaccessible places.

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Option(D) is correct

Option A : The method of the drug's distribution is irrelevant, unless the central authority can limit the drug's production from the bark of wild ibora trees. But this information is not provided.

Option B :  The cost of producing the drug does notaffect the outcome for the treeunless it deters production.

Option C :  The existence of uses for other parts of the tree opens the possibility that the ibora-bark drug would cause no increase in destruction of trees other than what exists already. If this information were provided, it would weaken support for the conclusion. Since it is not provided, this option does not significantly weaken the argument.

Option D :  Correct. This information most weakens the argument.

Option E :  Difficulty of access to the trees could provide a disincentive to their harvesting—but we are not told that it would prevent their harvesting.

The correct answer is D.

(4) Comment(s)


first option cannot weaken the above statment because it is basic common sense.


I think the third option is also correct as it weakens the argument that is stated above. Leaves are the source if they are taken back usage can be reduced :)


since the line is written in the above provided paragraph that "a tree that is quite rare in the wild." so the option e should be right bcoz it clearly weakening the argument by stating"the ibora generally grows in largely inaccessible places.


Hello, Mam you are taking question in wrong way the option e is simply equals to the line written "the ibora generally grows in largely inaccessible places"

but question is asked about the weakest argument i.e option d itself because in critical reasoning question you have find the answer from the passage only you don't have to use your own assumption till the matter is not mention . In option d the nothing is mention in the paragraph so it is weakest statement.

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