In 1988, a significant percentage of seals n the Baltic Sea died from

Question

In 1988, a significant percentage of seals in the Baltic Sea died from viral disease; off the coast of Scotland, however, the death rate due to viral diseases was approximately half what it was for the Baltic seals. The Baltic seals had significantly higher levels of pollutants in their blood than did the Scottish seals. Since pollutants are known to impair marine mammal’s ability to fight off viral infection, it is likely that the higher death rate among the Baltic seals was due to the higher levels of pollutants in their blood.

Which one of the following, if true, provides the most additional support for the argument?

(A) The large majority of Scottish seals that died were either old or unhealthy animals.

(B) The strain of virus that killed Scottish seals overwhelms impaired immune systems much more quickly than it does healthy immune systems.

(C) There were slight fluctuations in the levels of pollutants found in the blood of Baltic seals.

(D) The kinds of pollutants found in the Baltic Sea are significantly different from those that have been detected in the waters off the coast of Scotland.

(E) Among marine mammals other than seals, the death rate due to viral diseases in 1988 was higher in the Baltic Sea than it was off the Scottish coast.

globaldesi · Answer

In 1988, a significant percentage of seals in the Baltic Sea died from viral disease: off the coast of Scotland, however, the death rate due to viral diseases was approximately half what it was for the Baltic seals. The Baltic seals had significantly higher levels of pollutants in their blood than did the Scottish seals. Since pollutants are known to impair marine mammal’s ability to fight off viral infection, it is likely that the higher death rate among the Baltic seals was due to the higher levels of pollutants in their blood.

Which one of the following, if true, provides the most additional support for the argument?
 Additional support 
given: pollutants are known to impair marine mammal’s ability 
conclusion: higher death rate among the Baltic seals was due to the higher levels of pollutants in their blood

We have to find the connection between impair marine mammal’s ability and death caused by bacteria.

B uses this reasoning well
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(A) The large majority of Scottish seals that died were either old or unhealthy animals.  Irrelevant to pollution

(B) The strain of virus that killed Scottish seals overwhelms impaired immune systems much more quickly than it does healthy immune systems. : correct as explained
 
 (C) There were slight fluctuations in the levels of pollutants found in the blood of Baltic seals. Irrelevant

(D) The kinds of pollutants found in the Baltic Sea are significantly different from those that have been detected in the waters off the coast of Scotland. Weakens

(E) Among marine mammals other than seals, the death rate due to viral diseases in 1988 was higher in the Baltic Sea than it was off the Scottish coast. Irrelevant

B is the answer IMO

GMATking94 · Answer

Option C is not the correct answer choice since it says "The strain of virus that killed Scottish seals overwhelms impaired immune systems much more quickly than it does healthy immune systems." which in a way weakens the point that pollution was the real reason. We have to prove that pollution is the main culprit.

Option A is out of scope.

Option E though not clear, it is the best answer choice since it means there was one common issue.

kinteria · Answer

I think it can't be B because it says that “the strain of virus overwhelms impaired immune systems much more  quickly  than it does healthy immune systems". This doesn’t necessarily mean that the seals with impaired immune systems die more often than the ones with healthy immune systems. It would be too much of a long shot to assume that because the virus affects seals with impaired immune systems quicker, they have a higher mortality. It could well be that healthy seals die just in a prolonged time. Very tricky question but just as GMATNinja says “pay attention to any small modifier”; this can totally change the intended meaning of an argument or an answer option.

gmatgandalf · Answer

How is the answer (E) for this question? Is it because out of all the choices, this answer choice gives us a little more confidence that the higher level of pollutants was the cause of the higher death rate?

hotshotrk · Answer

Pre thinking : Anything that goes in line with this - the reason for death of Batlic seals is due to high levels of pollutants in their blood compared to Scottish seals. OR Baltic seas had higher amount of pollutants than the waters off the coast of Scotland.

A  - Introduces a new factor for death (Goes against our pre-thinking = weakener?)
 B  - Does not compare the 2 scenarios given in the passage (Baltic vs Scotland). This instead compares healthy vs impaired.
 C  - Irrelevant
 D  - Now introduces a new factor, which is the type of pollutant. This kinda weakens the argument as it deviates from the author's line of thinking.
 E  - This gives a scenario where other marine life also had higher death rate due to viruses in Baltic Sea vs Scotland (Similar to our prethinking). This essentially gives us reason to speculate that there was something wrong in the Baltic sea compared to the coastal waters off Scotland as it's not just the seals that were affected.

Dbrunik · Answer

im having a hard time understanding how this is a 95% hard question, as i was able to solve it with a solid understanding in 3 minutes and 17 seconds. the key reasoning is that the polutions are the cause of the baltic s's dying off. if other mammals also have high infection rates in the same area, then that strengthens the idea that it is from the toxins (that weakened the immune system) as opposed to some other outside variable (or the diseases themselves) .

bb · Answer

This is a hard question.  This took 5+ minutes to sort out in my head.  
I would not have been able to figure this out on the test and would have guessed E most likely as I disliked it less here is the analysis of the answer choices:

A)  is irrelevant 
 B)  talks about the Scottish seals, telling us that they died because of a certain virus. This requires us to assume that the same strain of virus killed both populations and I think that's too much of an assumption on the GMAT.
 C)  is incomplete and irrelevant. We do not know which seals it is talking about - all, dead, or alive and we do not know if they had a lot or little pollution. 
 D)  Weakens the argument 
 E)  The key to this question and this answer choice is this line:

Since pollutants are known to impair  marine mammal’s ability to fight off viral infection , it is likely that the higher death rate among the Baltic seals was due to the  higher levels of pollutants  in their blood.

So we know that marine mammals can't fight viral diseases well if they have a lot of pollutants in their blood. Because lots of other (not seals) marine mammals died due to viral diseases, this eliminates the potential weakener, which would be as follows: if marine mammals can't fight viral infections with high level of pollution, and you are telling me Seals died from viral diseases due to pollution, why aren't other marine mammals that are sharing the same space and food sources are dying too since they would also be subject to the same pollution and viruses? This answer choice ensures that the argument is not weakened by a logical contradiction. It does not strengthen it or fix it or prove it, it just eliminates a counter-argument. Pretty disappointing if you ask me.

P.S. The part I do not like about E is that we do not know if the sea is polluted or how pollution came to be. We are not told that. I think it would have been a much sounder question if it stated that the Baltic sea is highly polluted.

In 1988, a significant percentage of seals n the Baltic Sea died from

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In 1988, a significant percentage of seals n the Baltic Sea died from

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