Evaluate the Conclusion in Critical Reasoning

by on November 23rd, 2012

Today’s post comes courtesy of Veritas Prep GMAT instructor, Karishma.

At the risk of generalizing from a relatively small sample, let me say that people who are good at Quant, tend to be good at Critical Reasoning in Verbal. I certainly cannot comment about their SC and RC prowess but they are either good at CR right from the start or improve dramatically after just a couple of our sessions. The reason for this is very simple – CR is more like Quant than like Verbal. CR is very mathematical. You need to keep in mind some basic rules and based on those, you can easily crack the most difficult of problems. There is only one catch – don’t get distracted by options put there to distract you!

Today let’s discuss a great CR question from Veritas Prep. It frustrates many students even though it is simple – just like a GMAT question is supposed to be.

Question:

In the past 50 years, the population of honeybees in the United States has been cut in half. The decline is primarily due to the increasing use of pesticides in the United States, as well as to the introduction of two types of mites that weaken and kill the bees. Honeybees are the primary pollinators for a variety of important fruit crops, including oranges, apples, grapes, peaches, cranberries and watermelons. Therefore, if the honey bee population continues this drastic decline, then most fruits will no longer be available to consumers.

In evaluating the conclusion, which of the following questions would be LEAST useful to answer?

(A) Are there other insect pollinators that could pollinate these fruit crops instead of the honeybee?
(B) Are honeybee populations declining in other important fruit-producing regions, like Chile and New Zealand?
(C) Is it feasible for humans to hand-pollinate the fruits that have been pollinated by bees?
(D) Will reducing the use of pesticides in the United States reverse the decline in honeybee populations?
(E) Is it possible to genetically engineer fruit-producing plants so that they no longer require pollination?

Solution:

First notice the question stem. It’s an ‘evaluate the argument’ question. In all our strengthen/weaken questions we tell you to look at the conclusion. In this question, we have specifically mentioned ‘evaluate the conclusion’. Here the question clearly asks you to figure out what will not help in evaluating the CONCLUSION. So first step is to figure out the conclusion.

What is the conclusion in this argument?

We have a detailed discussion on how to find the conclusion of an argument in the Veritas Prep CR book. The conclusion in this argument is:

“If the honey bee population continues this drastic decline, then most fruits will no longer be available to consumers.”

The conclusion is that if the honey bee population continues to decline, then consumers will not get fruit. What you have to evaluate is this: if the honeybee population continues to decline, will the consumers get fruit? Mind you, we don’t have to evaluate whether the honeybee population will decline. Basically, we are wondering what will happen if the honeybee population continues to decline. We need to evaluate whether there are alternative ways of pollinating or getting fruit.

(A) Are there other insect pollinators that could pollinate these fruit crops instead of the honeybee?

Here we are looking for an alternative method of pollination. Finding the answer to this will help us evaluate whether consumers will get fruits if honeybee population continues to decline. Hence this is not the answer. One issue raised sometimes is that even if there are other insect pollinators, they will also get affected by the pesticide use and hence can’t be used for pollination. Remember here that we do not know whether all insects get affected by the pesticide use. It’s an ‘evaluate’ question. You first evaluate whether another insect can pollinate . Once you identify a possible pollinator, then you will evaluate the status of those insects and what affects them etc. You will be jumping the gun if you say that the same pesticides will affect every species of insects and hence no other possible pollinator can survive.

(B) Are honeybee populations declining in other important fruit-producing regions, like Chile and New Zealand?

Posing this question will help us evaluate whether there are alternative methods of obtaining fruit. Again, this helps us evaluate whether consumers will get fruit if honeybee population continues to decline.

(C) Is it feasible for humans to hand-pollinate the fruits that have been pollinated by bees?

Here we are looking for an alternative method of pollination. Finding the answer to this will help us evaluate whether consumers will get fruits if honeybee population continues to decline. Hence this is not the answer.

(D) Will reducing the use of pesticides in the United States reverse the decline in honeybee population?

This option trips most people. It is the answer but people find it hard to convince themselves that it is.

This question does not help us in evaluating whether consumers will get fruits. The conclusion clearly says that if the decline continues, fruits will not be available. We don’t have to question whether there are ways to reverse the decline. The point is – if the decline happens, can we do something. Say, I give you my opinion “If people keep fighting, the world will end.” You need to evaluate my opinion. What will you evaluate? Will you evaluate whether people will keep fighting or will you evaluate what happens when people keep fighting. In my opinion, if people keep fighting, the world will end. You need to find out what happens ‘if people keep fighting’. My opinion is based on a condition. You don’t have to question whether the condition will take place i.e. whether people will keep fighting or not.

Similarly, the conclusion states “if honeybee population continues to decline…”

Don’t worry about whether actually honeybee population will decline, stay the same or increase. Find out what happens if it continues to decline. Hence this conclusion is not useful and is the answer.

(E) Is it possible to genetically engineer fruit-producing plants so that they no longer require pollination?

Posing this question will help us evaluate whether there are alternative methods of obtaining fruit. Again, this helps us evaluate whether consumers will get fruit if honeybee population continues to decline.

Answer (D).

1 comment

  • Choice D is the correct answer because it is the one that is not directly focused on the conclusion, which is the prediction that most fruits will be unavailable in the absence of the honeybees. Choice D poses a very important question about a possible way to reverse the decline in the honeybee population, but the answer to this question would neither strengthen nor weaken the conclusion. Choices A and C ask about potential alternative ways to pollinate the fruit, while Choice E presents the possibility that pollination could be bypassed through genetic engineering. Choice B asks about other fruit-producing regions that might be used as alternative sources of fruit for consumers.

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