by WaltGrace1983 Thu Feb 20, 2014 2:40 pm
I got this one wrong, picking (D) instead of (E). I'll go through my entire thought process and show where I went wrong and where I went right. First of all, this is a necessary assumption question.
Amaryllis plants go dormant in their native habitat during the dry season
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If the Amaryllis plants are to thrive, they should go dormant for part of the year
So what is going on here? The premises are talking about what happens in their native habitat and the conclusion talks about what should happen in a household habitat. However, the big key word here is "thrive." Failure to understand the significance of this word is a failure to understand the argument in all of its complexity. So the gap here is between going dormant and thriving. The argument seems to assume that going dormant is necessary for thriving but is basing this conclusion on what happens in the plants' natural habitat. It is hard to pre-phrase necessary assumptions but this understanding should be good enough to attack the answer choices:
(A) Most kinds of plants go dormant? So? This is going way beyond the scope of the argument. We are talking about one plants, the amaryllis plant. Thus, what happens to other plants is not really relevant. We need something necessary, we are not merely trying to strengthen the argument - there is a big difference.
(B) I don't care if it is more difficult! We are not comparing the relative difficulty of keeping plants in this argument! What we are doing here is talking about the relationship between thriving and going dormant. Fortunately for us, this is such a scope shift that this is a quick elimination.
(C) I could see why this one could be a bit tricky. However, let's look at what that conclusion is saying again: "water should be withheld from them during part of the year..." It could be January, March, it could be for two days in November, maybe it will just be on Christmas. Who knows?! (C) is wrong because its not right; it is simply not necessary for this argument. We are not looking to place restrictions on when the plant should go dormant. We are looking to figure out that relationship between thriving and going dormant.
So here is where I was when doing this question. I actually eliminated (E) before I chose (D). Why did I do this? I was too concerned with the (perfectly okay) shift in what I thought was scope. Let's look at (E). The first part of (E) looked pretty good: "Going dormant benefits the plants..." This was generally what I was looking for. However, I was thrown off by the second part of the sentence talking about "native habitat." Yet this is perfectly okay because the premise is talking about native habitats and the premise is what we are basing the conclusion off of. If we negate (E) we get something along the lines of, "Going dormant really only benefits amaryllis plants because it prevents death." So all it does is prevent death? How would going dormant help it thrive then? Just simply preventing death is not thriving. Thus, this destabilizes the link between our premise and conclusion and that is why (E) is correct.
(D) is incorrect too. It does however have the conclusion spot on by saying that (__________ → thrives). In the heat of the moment, this is why I chose D; The conclusion of (D) was what we are looking for! However, the problem is the premise of this answer choice: (Dormant for the appropriate amount of time → thrives). We don't care about time in dormancy! We already established this with (C)! Time does not matter because nowhere does it say anything about the appropriate amount of time being dormant. All we know from the argument is: (dormant → thrive). For all we know, being dormant for 14 seconds is enough time.
All in all, (E) is the right answer.