CR TC 55 3

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CR TC 55 3

by SmarpanGamt » Tue Nov 09, 2010 12:46 pm
Dutch elm disease, which is caused by the fungus C. ulmi spread by adult scolytid beetles, has already destroyed 70 percent of the elms in Greenwood Forest. Another naturally occurring fungus, P. oblonga, kills larvae of the scolytid beetle. Forest rangers plan to introduce P. oblonga into Greenwood Forest in order to save the remaining mature elms.

Which of the following, if true, would cast the most serious doubt on the plan's prospects for success?

(A) During the last year, the scolytid beetle population in Greenwood Forest has decreased by 30 percent because of cold-weather conditions.
(B) Dutch elm disease cannot be abated by introducing chemical compounds used to arrest the diseases of many other species of tree.
(C) Introduction of P. oblonga saved elm trees in neighboring Gatemar and Lavemont forests.
(D) For P. oblonga to control scolytid beetles successfully, it must be established in a forest prior to the beetle infestation.
(E) Greenwood Forest has lost many maple trees because of a fungus infection

Please explain your choice OA later
Source: — Critical Reasoning |

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by Ravish » Tue Nov 09, 2010 1:19 pm
My pick is (D)

If the P. oblonga fungus is only effective if introduced prior to a beetle infestation, then introducing the fungus in the greenwood forest would not serve any purpose as Greenwood, as the question states, is already suffering from a beetle infestation.

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by SmarpanGamt » Tue Nov 09, 2010 1:33 pm
OK then lets look the option "D" as

D : For P. oblonga to control scolytid beetles successfully, it must be established in a forest prior to the beetle infestation

If the option was : P. oblonga is not established in the control scolytid beetles successfully. ( Then the option would weaken the point)


what if establish
Since the option opens in two folds ( If established and If not established) chosing this one was tricky. the option provides a step prior to the weakening point. however, option was a contenter for me but not the answer.
OA is D

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by RikaMueller » Sun Nov 21, 2010 3:56 am
so which one is the correct answer? B?