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Question
Boreal owls range over a much larger area than do other owls of similar size. The reason for this behavior is that the small mammals on which owls feed are especially scarce in the forests where boreal owls live, and the relative scarcity of prey requires the owls to range more extensively to find sufficient food.
Which of the following ,if true, most helps to confirm the explanation above?
(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)
Solution
Understanding the Passage
Boreal owls range over a much larger area than do other owls of similar size.
Boreal Owls >> Other Owls of similar size – in terms of size of area
The reason for this behavior is that the small mammals on which owls feed are especially scarce in the forests where boreal owls live, and the relative scarcity of prey requires the owls to range more extensively to find sufficient food.
The explanation for the fact given in the first statement is that
1. Food is scarce for Boreal owl i.e. less food per unit of area
2. Thus, more area required to get enough food to survive
While this could be an explanation for the larger range of Boreal owls, there could be other explanations too. For example, boreal owls are more aggressive than other owls and thus, by nature, keep a bigger area to themselves even when the food is not scarce.
Understanding the Question Stem
The question asks us to support the explanation. The 2nd statement is an explanation for the first statement.
In general, if X is given as an explanation for Y, we can strengthen the explanation by
1. suggesting that X is indeed an explanation for Y
a. by eliminating other explanations
b. by presenting an example in which the absence of X meant the absence of Y
2. suggesting that X indeed happened if the existence of X itself can be questioned. (In other words, if we are not even sure whether X has happened, we can strengthen “X is the explanation for Y” by indicating that X has happened. If we already know, as a fact, that X has happened, then we cannot strengthen the argument by indicating that X has happened.)
Please note that “X is an explantion for Y” can NEVER be strengthened by saying that Y indeed happened. You can think about it.
In this question, Y = “Boreal Owls >> Other Owls of similar size – in terms of size of range”
X = “Food is scarce for Boreal owl i.e. less food per unit of area. Thus, more area required to get enough food to survive”
Options Evaluation
(A) Incorrect.
This option just supports the fact (Y), whose explanation is given. However, as stated above, “X is an explanation for Y” can NEVER be supported by supporting Y.
(B) Correct.
The fact that food eaten by small mammals is sparse indicates that small mammals are sparse in those regions. Think about it. If food for a species in a region is sparse, NOT many members of the species can exist in that region. Simply because there is not enough food.
Thus, this option means that boreal owls range over larger areas in regions where small mammals are sparse than they do in areas where small mammals are abundant.
Thus, this option indicates that the density of boreal owls in a region is dependent on the sparsity or density of their food in the region. Thereby, this option strengthens the explanation that the reason boreal owls range over larger areas than other owls is sparsity of their food.
(C) Incorrect.
This option presents a comparison between two stages of boreal owls: before their young hatch and after their young hatch. However, this option doesn’t suggest any reason why boreal owls range over larger areas than other owls.
(D) Incorrect.
This option indicates that sometimes (which means at least once), individual boreal owls can find enough food in a small region.
Let’s make this option stronger by changing “sometimes” to “most of the times”
Most of the times, individual boreal owls hunt near a single location for many weeks at a time and do not range farther than a few hundred yards.
This variation casts a doubt on the fact that boreal owls range over larger areas than other owls. This variation has no impact on the explanation; this changed option casts doubt on whether Y didn’t happen. This can never impact the statement that X is an explanation for Y.
(E) Incorrect.
This option can weaken the explanation rather than strengthen it. If boreal owls require less food, then they don’t need to range over larger areas because of sparsity of food. If they need less food, they can find that food in the same size of the areas as other owls do.
In this case, the sparsity of food may not be able to explain the larger range of boreal owls.
Chiranjeev Singh
An Alumnus of IIM Ahmedabad and with scores of 735 (2024) and 780 (2017) on the GMAT and 99.98%ile on CAT, Chiranjeev is one of the most qualified GMAT tutors in India. Chiranjeev has earlier served as Director of Curriculum at e-GMAT. Chiranjeev has been helping students ace GMAT since 2012. He follows a concept-based methodology to teaching GMAT and is very committed to student success. You may contact him for any private GMAT tutoring needs at CJ@GMATwithCJ.com. He conducts online sessions for students across the world.
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