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

Question

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

sanjitscorps18 · Answer

IMO it should be E

A. Whether the harmful insect is preyed upon by any other predators, be they insects or small creatures -  Would not explain the spiders eating other insects

B. Whether the particular breed of spider chosen also causes harm to watermelons due to its nesting -  Not relevant

C. Whether the number of spiders equalled the number of watermelon pests after one month -  Not relevant

D. Whether the field already contained spiders that perhaps prey upon the watermelon pests -  Not relevant

E. Whether previous population figures for the watermelon pest show an increase over time -  Checking this would help to establish if the spiders did their intended work

sumitkrocks · Answer

Option (E) suggests in the absence of Spider the number of insects would have increased. Hence, Spider has fed on the insect.

(E) is correct

100mitra · Answer

Correct Option : E

Conclusion 
Results of the experiment showed that
-  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.

Most useful to establish in order to evaluate the argument?
- Pest decreased or Not?

A. -  Wrong  - preyed upon by any other predators - No information about pest reduction
B. -  Wrong  - selection of breed of spider - No information on pest reduction
C. -  Wrong  - The number of spiders equalled the number of pests - We need pest to pest comparison before and after project implementation
D. -  Wrong  - Conditional flaw, no conclusion is derived + irrelevant
E. -  Correct  - Pest population before and after, correctly evaluate project

Posted from my mobile device

sivatx2 · Answer

Premise 1: a spider feed on certain insect & reduce their numbers 
Premise 2: spiders were allowed to feed & monitored 
Premise 3: Number of insects remain same, after the experiment. 
=> Conclusion: spiders must have eaten other insects & not their intended prey.

Crucial Factor( to evaluate most useful): One that establishes the relevancy(interdependency/independence) between the 2 events, 1. spiders feeding and 2. the number of insects preyed, will determine the experiment was successful or not.

A. Whether the harmful insect is preyed upon by any other predators, be they insects or small creatures
  
  Does this help to evaluate the argument? No. There could be N type of creatures who can prey on the insect. But it is not going to help us evaluate the relevancy between whether 1. spiders feeding and 2. the number of insects preyed.
Eliminate.

B. Whether the particular breed of spider chosen also causes harm to watermelons due to its nesting  
 Harm to watermelon is out of scope, as the number of insects remained same and this cannot evaluate the given argument. Eliminate

C. Whether the number of spiders equalled the number of watermelon pests after one month  
  This is totally irrelevant to evaluate the argument, as the actual number of spiders does not matter at all. Eliminate .

D. Whether the field already contained spiders that perhaps prey upon the watermelon pests  
  If the field already had spiders, why did they experiment with the same spider type again? This must be false as after additional spider, the pest count remains the same. Eliminate.

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

This will help to evaluate the argument, if the pest were previously increasing significantly, then it is understood they had previously rise in population, which has been contained by the spiders and hence, the experiment worked. 
If the pest population were declining or staying constant, then it is understood, that the introduction of the spider had either negative impact( spiders eating something else or allowed preys to sustain) or at least no impact, and hence the experiment failed.   
  Since we can concretely say that this will help to evaluate the argument, the correct answer choice is E.

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

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

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