In a recent experiment, a spider breed was chosen as a

[BTGmoderatorDC]

In a recent experiment, a spider breed was chosen as a potential natural pesticide to reduce the numbers of a certain insect that is very harmful specifically to growing watermelons. In an average infested watermelon field, tagged spiders were released, and their feeding monitored for a month. Results of the experiment showed that although the spiders ate extremely well, the number of pests remained the same as the month before. Therefore, the spiders must have eaten other insects and not their intended prey.

Which of the following would it be most useful to establish in order to evaluate the argument?


A. Whether the harmful insect is preyed upon by any other predators, be they insects or small creatures

B. Whether the particular breed of spider chosen also causes harm to watermelons due to its nesting

C. Whether the number of spiders equalled the number of watermelon pests after one month

D. Whether the field already contained spiders that perhaps prey upon the watermelon pests

E. Whether previous population figures for the watermelon pest show an increase over time




OA E

Source: Economist Gmat

[deloitte247]

Premise: In a recent experiment, a spider breed was chosen as a potential natural pesticide to reduce the number of a certain insect that is very harmful specifically to growing watermelon.

Conclusion: Although the spiders ate extremely well, the number of pests remained the same as the month before. Therefore, the spiders must have eaten other insects and not their intended prey.

Option A - Incorrect:
This option cannot evaluate the argument because a spider breed was chosen as a potential natural pesticide. Hence, we have no idea about other predators that must have preyed upon the harmful insects.

Option B - Incorrect:
We can't know if this claim is true as there is no information about the harmful effects of the spider breed chosen.

Option C - Incorrect:
There is no evidence to back up this claim because we are not concerned about the number of spiders in the field. Therefore, this option is invalid.

Option D - Incorrect:
This option is false because if the field already contained spiders, the number of pests in the field would not remain the same. Hence, the field didn't contain spiders that preyed upon watermelon pests.

Option E - Correct:
This option evaluates the argument. Results of the experiment showed that the spiders ate extremely well, this shows that the spiders preyed upon the pests yet the number of pests remained the same, which is as a result of the increase in the watermelon pests.