Logical reasoning PrepTest 156 · Section 2 · Question 24

Question prompt

Researcher: Several chemical compounds Remaining source text redacted.
Why the credited answer is right

Credited answer: A

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Strategy Overview

Argument or facts? Always argument, so identify premises and conclusions of argument Anticipate why the premises are not enough to show that the conclusion is true
Causal argument? Look for answer choice that:
Shows possible alternate cause Shows cause without effect Shows effect without cause Shows the cause and effect are reversed
If not causal argument, anticipate ways to worsen problem with argument
Use anticipations to eliminate the answer choices that weaken the argument and select an answer choice that does not weaken the argument.

Answer Anticipation

This is a Bizarro Weaken question, so the argument has to be flawed enough that four different answer choices can weaken it. And this one is very flawed indeed! There are several common flaws committed here. Causation flaws are rampant on Weaken questions, and this researcher's argument is no exception. The researcher's conclusion asserts that isoflavones and phytosterols are "effective agents" for cancer prevention. The researcher's premise/conclusion also claims that phytosterols have "anticancer effects." The use of causal words like "agent" and "effect" suggests that the researcher thinks isoflavones and phytosterols will cause the risk of cancer to be lower. The researcher's premises explain how each compound can reduce a compound associated with cancer. When an argument on a Weaken question commits a causation flaw, the correct answer — or, in the case of a Bizarro Weaken question, the incorrect answers — will probably describe one of the common cause-and-effect weakeners. The two most common weakeners undermine the correlation between the alleged cause and the effect. So, the incorrect answers might show the cause appearing without the effect (the consumption of isoflavones or phytosterols and a higher risk/incidence of cancer) or the effect appearing without the cause (a lower risk/incidence of cancer and lack of isoflavones or phytosterols). We probably won't see the third most common cause-and-effect weakener — an alternative cause — since the researcher doesn't cite an observed effect in the premises. Speaking of a lack of an observed effect in the premises, that's another problem with this researcher's argument. The researcher assumes that because isoflavones reduce estrogen production in rats and other mammals, they must reduce the risk of cancer. But the researcher never shows that these rats and larger mammals suffer from cancer less often than a control group. Perhaps isoflavones don't reduce estrogen enough to reduce the risk of cancer. Or maybe they promote another hormone that increases the risk of cancer. Likewise, the researcher says that phytosterols slow cholesterol absorption, but there's no study that says the consumption of phytosterols is associated with a lower risk of cancer. The incorrect answers may point to one of these issues. Finally, there's the issue of using "rats and larger mammals such as cheetahs and sheep" to make a conclusion about humans. We don't know that these animals respond to the isoflavones in soybeans in a similar manner as humans. Perhaps the effects we observe in animals cannot be replicated in humans. There are other issues with this argument (for instance, notice how a premise asserts that phytosterols "may" reduce cholesterol and the premise/conclusion says they definitely have anticancer effects), so we can keep an open mind as we assess the answer choices. But we should be able to use these anticipations to help us eliminate most or all the wrong answer choices. The correct answer choice will not weaken the argument. It could be irrelevant or even strengthen the argument by fixing one of these problems.

Answer choices

  1. A
    The soybean derivatives used Remaining source text redacted.
    Why choice A matches the stem

    This isn't related to one of the problems we identified in the argument, so we should carefully assess this answer choice to see if it weakens the claim that isoflavones and phytosterols are "effective agents" for cancer prevention. So, what happens to that argument if the soybean derivatives used in most studies come from specialized processing techniques and are not yet widely available?

    Well, nothing, really. This answer choice tries to make us think the researchers' premises (that isoflavones reduce estrogen production in rats and larger mammals and phytosterols may reduce cholesterol absorption) come from studies that use these soybean derivatives. This answer choice also wants us to think that if these studies use soybean derivatives, their findings may be unreliable — the effects produced by these soybean derivatives may not resemble the effects produced by the actual soybeans available to the public.

    But, first of all, we don't even know that these premises come from studies using these soybean derivatives. After all, the soybean derivatives are used in "most," not all, studies. Perhaps these premises come from studies that trace the effects of actual soybeans.

    Secondly, even if these premises come from studies that use these soybean derivatives, we can't simply assume that the effects of soybean derivatives are meaningfully different than the effects of actual soybeans. If this answer choice gave us any reason to believe the effects were different, this answer choice might be more appealing. But the only thing we know about the soybean derivatives is that they come from "specialized processing techniques" and are not widely available to consumers. Even if they're processed and can't be purchased on the market, they could still produce the same effects as regular soybeans. So, eliminating (A) would require us to make an unjustified assumption about soybean derivatives.

    Since we can't find a reason why this would weaken the researcher's argument, we can mark (A) as a strong contender. It's pretty risky to select the first answer that seems right on a Bizarro Weaken question — this answer choice could exploit a problem we didn't identify in the argument. So, let's quickly review the remaining answer choices. If they all exploit flaws we identified in the researcher's argument, we can select (A) confidently.

  2. B
    While phytosterols, which occur Remaining source text redacted.
    Why choice B is not credited

    This weakens the argument by undermining the correlation between phytosterols and cancer reduction. As we anticipated, it does so by presenting the cause ("phytosterols ...decrease cholesterol absorption ...") without the effect (" ... this decrease is not large enough to reduce susceptibility to cancer"). So, this answer choice shows that one of the chemical compounds in soybeans probably isn't an "effective agent[] for cancer prevention in humans," thus weakening this researcher's argument.

  3. C
    A study of people Remaining source text redacted.
    Why choice C is not credited

    Like (B), this weakens the argument by undermining the correlation between phytosterols and cancer reduction. This time, it hones in on the relationship between soybeans/phytosterols and cholesterol reduction. (C) presents the cause ("soybean-rich diet ...") without the effect (" ... no significant reduction in cholesterol levels"). So, this answer choice shows that phytosterols may not slow cholesterol absorption and, therefore, may not "have anticancer effects."

  4. D
    Consumption of soybean products Remaining source text redacted.
    Why choice D is not credited

    This weakens the argument by pointing out a problem with relying on a premise about isoflavones' effects on animals. It establishes that the soybeans' effects on animals do not mirror soybeans' effects on humans, which makes us question the premise about isoflavones' ability to inhibit estrogen in humans.

    We can also think of this answer choice as providing another example of "cause without the effect." Like (B) and (C), this presents the cause ("people whose major source of protein is soybeans ...") without the effect ("... showed blood cholesterol levels no lower than normal"). Once again, this answer choice suggests that phytosterols may not slow cholesterol absorption or "have anticancer effects."

  5. E
    Preliminary studies have not Remaining source text redacted.
    Why choice E is not credited

    Like (D), this weakens the argument by pointing out a problem with relying on a premise about isoflavones' effects on animals. This answer choice suggests isoflavones affect humans differently than they affect animals. Isoflavones may decrease estrogen in some animals, but they don't change humans' estrogen levels. If isoflavones don't affect humans' estrogen levels, they may not reduce the risk of cancer in humans.

    We can also think of this answer choice as providing another example of "cause without the effect." Like the other wrong answer choices, this presents the cause ("isoflavones ...") without the effect ("... have no shown ... significant effect on estrogen levels in humans"). So, this answer choice suggests that isoflavones may not reduce estrogen or help prevent cancer.

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A Credited 53%
  2. B 14%
  3. C 10%
  4. D 13%
  5. E 11%

Deeper help

Ask follow-ups on any step

Optional AI tutor mode will let you interrogate assumptions, compare answers, and drill weak patterns without leaving the page.

Human-written explanations stay primary; AI is an add-on when you want it.

Discussion

No threads yet—be the first to ask a question or share an approach.

View all discussions Start a discussion