Bunuel wrote:
Studies suggest that, for the vast majority of people who have normal blood pressure, any amount of sodium greater than that required by the body is simply excreted and does not significantly raise blood pressure. So only persons who have high blood pressure and whose bodies are incapable of safely processing excess sodium need to restrict their sodium intake.
Which one of the following, if true, would most seriously weaken the argument?
(A) High blood pressure is more harmful than was previously believed.
(B) High blood pressure is sometimes exacerbated by intake of more sodium than the body requires.
(C) Excess sodium intake over time often destroys the body’s ability to process excess sodium.
(D) Every human being has a physiological need for at least some sodium.
(E) Any sodium not used by the body will increase blood pressure unless it is excreted.
EXPLANATION FROM Fox LSAT
- Premise: For people with normal blood pressure, excess sodium is usually harmlessly excreted, without raising blood pressure.
- Conclusion: So we don’t have to worry about excess sodium unless we have high blood pressure or limited ability to excrete sodium.
We’re asked to “seriously weaken” the argument. So we want to put a wedge in-between the premise and the conclusion. The argument sounds fairly reasonable to me, so I don’t have a great prediction going into the answer choices. Let’s just try to pick the answer choice that seems to do the most damage to the argument.
A) I don’t see how this weakens the argument. High blood pressure could be instantly fatal, and I still don’t think it would weaken the argument. The argument says we’re not going to
get high blood pressure from excess sodium, so who cares how lethal it is? I don’t think this is the answer.
B) This wouldn’t weaken the argument, because the argument explicitly says it doesn’t apply to people with high blood pressure.
C) If this is true, then even healthy people should probably avoid excess sodium, lest they eventually become one of the people whose bodies cannot process excess sodium properly. I like this answer.
D) The argument concludes that only certain people needed to
avoid sodium. If this answer is true, it would strengthen the idea that sodium shouldn’t be avoided. We wanted a weakener, but this is a strengthener.
E) This wouldn’t weaken the argument, because the argument explicitly says it only applies to people who don’t have a problem excreting excess sodium.
Our answer is C.
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