Critical Reasoning

Source: OG Verbal Review 2nd Edition

Certain messenger molecules fight damage to the lungs from noxious air by telling the muscle cells encircling the lungs' airway to contract.This partially seals off the lungs.An asthma attack occurs when the messenger molecules are activated unneccessarily,in response to harmless things like pollen or household dust.

Which of the following,if true ,points to the most serious flaw of a plan to develop a medication that would prevent asthma attacks by blocking receipt of any messages sent by the messenger molecules referred to above？

(A)Researchers do not yet know how the body produces the messenger molecules that trigger asthma attacks.

(B)Researchers do not yet know what makes one person's messenger molecules more easily activated than another's.

(C)Such a medication would not become available for several years,because of long lead times in both development and manufacture.

(D)Such a medication would be unable to distinguish between messages triggered by pollen and household dust and messages triggered by noxious air.

(E)Such a medication would be a preventative only and would be unable to alleviate an asthma attack once it had started.


Can some explain in detail this problem?

IMO D

Think about the main plan: " to block the messages sent from messenger molecules"
Why we are doing this: "To prevent asthma attack from pollen or other "harmless" molecules"
What would weaken this: "Anything "harmful" that might not be blocked because of this"


D--> we are not blocking the toxins because we inhibited the messenger molecules. Thus, this is the best attack against the plan.

D is correct. Imagine that a store has problem with shoplifters, so the manager hires security to guard the door and keep suspicious-looking people from leaving. But the security guard can't figure out which people are shoplifters, so he detains every single customer at the door, and won't let anyone through. That's kind of what's happening here with the messenger molecules; in choice D, the blocking medication can't figure out which molecules are good, and which ones are bad, so it just goes after all of them. That's a major weakness.

Thanks for explanation

Looking at it now, D makes sense