#7 - Researcher: Accurate readings of air pollution are

[Administrator]

Complete Question Explanation

Strengthen. The correct answer choice is (E)

This researcher discusses the collection of accurate air pollution readings, which can be expensive,
and one possible alternative that might provide a cheaper approach. Lichens are organisms that
absorb air pollution, so the researcher collected samples of the plant-like substance from sites that
were known to have high levels of copper pollution. The copper concentrations in the lichens were
compared with the concentrations found with standard pollution-monitoring equipment. Since the
lichens’ results were as accurate as those acquired with mechanical devices, the researcher concludes
that lichens can provide an effective replacement for more expensive devices, without losing
information.

The question that follows asks for the answer choice that strengthens the researcher’s argument, so
the correct answer choice will be the one that helps to justify the author’s conclusion that lichens can
replace more expensive pollution monitoring equipment without losing any information.

Answer choice (A): The researcher’s conclusion is that the lichens can replace more expensive
monitoring devices, so the question of whether or not such devices have been installed is not
relevant. Since this choice does not bolster the researcher’s argument, it cannot be the correct answer
to this Strengthen question.

Answer choice (B): The stimulus established that lichens absorb copper, but copper’s appearance
elsewhere does not bolster the more general claim that lichens can provide a general substitute for
more expensive pollution-monitoring systems.

Answer choice (C): The lichens’ reaction to unpolluted conditions is not relevant to the researcher’s
claim that lichens can be used to effectively monitor air pollution, so this choice does not strengthen
the author’s argument and cannot be the right answer to this Strengthen question.

Answer choice (D): The researcher suggests that lichens harvested from the sites of pollution can
provide accurate information about that pollution. The ability to grow lichens in the lab does not
bolster the researcher’s argument.

Answer choice (E): This is the correct answer choice. Answer choice (E) tells us that lichens absorb other major air pollutants in the same way they absorbs copper. This strengthens the argument by giving us evidence that lichens may be able to monitor other air pollutants in the same way they monitor copper and thus could potentially replace pollution-monitoring devices. Sure, it doesn't prove that lichens could effectively replace those devices without loss of information. But it certainly helps out that conclusion, and that's all we're being asked to do here. Don't get caught up in the thinking that "manner similar" just means it's the "same mechanism." All answer choice (E) is saying is "You know how lichens absorb copper? It does the same thing with other pollutants." Since that absorption of copper is what allows us to use lichens to monitor carbon pollution, then the fact that lichens also absorb other air pollutants suggests that we can probably use lichens to monitor those other pollutants in the same way. And, again, we only need that idea of it will probably work...we don't need to be 100% certain to strengthen.

[ShannonOh22]

Please provide some clarification on why A is incorrect...the author's conclusion is that "lichens can effectively replace expensive pollution-monitoring devices without the loss of information". A states "mechanical monitoring devices have not already been installed in areas where air pollution is a serious problem". Seeing as the conclusion specifically mentions "expensive", would not the statement that money had not ALREADY been spent on these machines strengthen the argument immensely?

Answer choice E (which, for the record, was my initial choice, but I switched because it didn't directly address the conclusion) is more subjective, and therefore harder to defend.

A more factual and monetary point of strength would be in that the machines have not already been paid for and installed, would it not?

Please help clarify, thank you!

[James Finch]

Hi Shannon,

The big difference between (A) and (E) comes down to the scope of the conclusion in the stimulus, which is that lichens can effectively replace the machines, not that they should or would. All we're trying to help prove is the ability of the lichens to perform as well as the machines at reading air pollution levels--and crucially, all air pollution levels, not just the copper that the stimulus talks about. This is why (E) is able to help, as it can be used to extend the copper experiment findings out to all air pollutants, while (A) doesn't, as it doesn't matter whether there already are devices measuring the air pollution levels or not, just whether lichen could theoretically do as good a job as they do.

Hope this clears things up!

[ShannonOh22]

Aha - makes perfect sense. Thank you again, James!

[dbrowning]

This question gave me trouble. I was between B and E, and I skipped to return at the end of the section. I still ended up missing it. If you look at what AC E is actually saying, it states that, essentially, 'the mechanism (way) by which lichens absorb copper is similar for other air pollutants.'. I still do not see how this strengthens the argument. The gap between the premises and conclusion is that, even though lichens were effective for copper, they may not be effective in monitoring the other air pollutants - hence there could be a loss in information. AC E still leaves open the possibility that lichens ineffectively absorb and monitor all other air pollutants (the gap between premises and conclusion), even if they absorb them in the same way. Analogously, I would lift a 5 lb weight the same way I would life a 100lb weight, but I certainly would not do so as effectively (or even effectively at all).

I disliked every AC on this question, because none adequately addressed the gap between the premises and the conclusion. My reason for siding with B over E is that it at least sets a minimum floor for the possible scope of instances in which lichens can replace equipment.

[KelseyWoods]

Hi dbrowning!

Remember that in a Strengthen question, we don't need to prove the conclusion 100%, we're only being asked to help it out as much as possible. Here, we're being asked to support the claim that lichens can effectively replace expensive pollution-monitoring devices without loss of information. Based on the premises, all we know is that lichens are accurate as accurate at monitoring airborne copper pollution as the best equipment available. The leap between the premises and the conclusion, then, is the leap from "lichens can effectively monitor copper pollution" to "lichens can effectively monitor ALL pollution." Answer choice (E) tells us that lichens absorb other major air pollutants in the same way they absorbs copper. This strengthens the argument by giving us evidence that lichens may be able to monitor other air pollutants in the same way they monitor copper and thus could potentially replace pollution-monitoring devices. Sure, it doesn't prove that lichens could effectively replace those devices without loss of information. But it certainly helps out that conclusion, and that's all we're being asked to do here. Don't get caught up in the thinking that "manner similar" just means it's the "same mechanism." All answer choice (E) is saying is "You know how lichens absorb copper? It does the same thing with other pollutants." Since that absorption of copper is what allows us to use lichens to monitor carbon pollution, then the fact that lichens also absorb other air pollutants suggests that we can probably use lichens to monitor those other pollutants in the same way. And, again, we only need that idea of it will probably work...we don't need to be 100% certain to strengthen.

Hope this helps!

Best,
Kelsey

[bagelover]

Hi, I had a question regarding answer choice A. )
In the conclusion of the argument, it mentioned "loss of information", which made me ultimately decide on A. My reasoning is that, since mechanical devices haven't been installed yet, installing the lichens won't interfere with the "loss of information" in regards to replacing because they aren't there yet.

How is answer choice E.) better in this regard? Is my consideration even in scope of the argument?

Thank you!

[Dave Killoran]

Hi Bage,

With (E), Kelsey made a great explanation above. But to put it another way, what (E) is driving at is that the lichens will work for all kinds of air pollution, not just copper. This really helps because the conclusion had a really broad aspect to it--not that the lichens would help with just copper pollution monitoring, but with full replacement of pollution-monitoring devices, which would handle all sorts of different types of pollution. So knowing they work for all types is very helpful.

With your explanation of (A), to me the "loss of information" in the stimulus is a comparison between lichens and mechanical monitoring devices--as in, the lichens aren't informationally worse or inferior to mechanical devices according to the Researcher. That aside, the argument is about lichens being a reasonable replacement that is more cost-effective overall. When we take (A) as true, does this have any effect on the argument of lichens being a reasonable replacement? No, it just tells us that there looks like a sizable market for air pollution monitoring, but it doesn't tell us if the lichens are as good or cheaper.

If we were to compare (A) and (E), answer choice (E) is giving us a piece of information that helps us understands that lichens can do the job; answer choice (A) doesn't do that, it just tells us there's a lot of places that can use monitoring.

Thanks!