We’ve got a Main Conclusion question which we know from the question stem: Which one of the following most accurately expresses the main conclusion of the argument?
Moving onto the stimulus:
We start out with the notion that chemical fertilizers are very bad for a couple reasons: 1) they create health issues and 2) they kill worms, which are beneficial for soil.
Then we get the word “for” which some of you may recognize as an indicator that precedes a premise but is often part of a sentence that also includes a conclusion. Interesting. Is that the case here? Let’s take a closer look.
We’re told “for this reason.” What reason? Well “this reason” is a referential phrase referring to the second effect of chemical fertilizers we were presented with in the opening sentence. If we insert the information that “this reason” is referring to and paraphrase a bit, the second sentence would read like: “Because fertilizers destroy earthworms, the use of chemical fertilizers should be avoided.” So now we can see that the opening clause of this sentence provides support for the second clause. We can apply the why test just to make sure: Why should we avoid chemical fertilizers? Well because fertilizers destroy earthworms. The only way we can work out the full meaning of this sentence though, is by unpacking the referential phrase within it. Ok so we’ve identified at least one premise and conclusion. Now let’s move on to the third sentence.
If we look closely at the third sentence we see the word “thus” which is a conclusion indicator. But I thought we already found our conclusion? Not so fast! We found one conclusion! That doesn’t mean there can’t be more! When we take a closer look, we find a conclusion in the second clause of this sentence immediately following the word thus: “a garden rich in earthworms is much more fertile than a garden without them.” Working backwards we can see support in the first clause of this sentence. Again, we can apply the why test to test this support relationship: Why is a garden rich in earthworms much more fertile than a garden without them? Well because the castings they leave behind are richer than the soil they ingest. That works! First clause premise, second clause conclusion.
Ok so now we’ve got two conclusions, but only one of these can be our main conclusion meaning one of them is a sub-conclusion that both lends and receives support. If we take a step back, we see that the second conclusion supports the idea that chemical fertilizers should be avoided, meaning that this first conclusion about chemical fertilizers is our main conclusion. Let’s return once more to our old friend Mr. Why Test: Why should the use of chemical fertilizers be avoided? Well because our first premise tells us that fertilizers kill earthworms and our sub-conclusion tells us that a garden rich in earthworms is much more fertile than a garden without them. Now that’s what I call support!
Ok so let’s revisit our main conclusion: “the use of chemical fertilizers should be avoided.” Let’s take a look at our potential answers:
Answer Choice (A) This correctly sums up our premise but is not part of our conclusion.
Answer Choice (B) Again, this refers, correctly to another aspect of our premise, but is not found in our conclusion.
Answer Choice (C) Another answer choice that accurately sums up one of our premises, but not our main conclusion.
Correct Answer Choice (D) This is verbatim the main conclusion we identified. Not much more we need to discuss there. Case closed. But since we’ve still got one more answer choice left, let’s go ahead and take a look.
Answer Choice (E) Ok yet another answer choice that correctly sums up part of our stimulus. In this case this is referring to our sub-conclusion. If you didn’t recognize that this is a sub-conclusion that actually supports our main conclusion, this might be a tempting AC.
A
For many of the atypical Parkinson’s patients, their symptoms stopped getting worse, and in some cases actually abated, when they stopped eating soursop, custard apple, and pomme cannelle.
B
Of the healthy adults who did not regularly eat soursop, custard apple, and pomme cannelle, most had eaten each of these fruits on at least one occasion.
C
In areas other than Guadeloupe, many people who have never eaten soursop, custard apple, and pomme cannelle have contracted atypical Parkinson’s.
D
The 10 healthy adults who regularly ate soursop, custard apple, and pomme cannelle ate significantly greater quantities of these fruits, on average, than did the 35 atypical Parkinson’s patients.
E
Soursop, custard apple, and pomme cannelle contain essential vitamins not contained in any other food that is commonly eaten by residents of Guadeloupe.
Albrecht: Shareholders typically have diversified investment portfolios. For employees, however, the well-being of the corporation for which they have chosen to work represents their very livelihood. The corporation’s primary responsibility should be to them.
A
corporations have a responsibility to their shareholders
B
corporations are responsible for the welfare of their employees
C
means should be provided for a corporation’s investors to recoup their losses if the corporation goes bankrupt
D
a corporation’s shareholders have more at stake than anyone else does in the corporation’s success or failure
E
the livelihood of some of the shareholders depends on the corporation’s success
A
Banks initially process all transactions using one set of computer programs, but then use a different set of programs to double-check large transactions.
B
Recent changes in banking standards require that customers present identification both when making deposits into their accounts and when making withdrawals from their accounts.
C
Banks are required by law to send each customer a monthly statement detailing every transaction of the previous month.
D
The average ratio of bank auditors to customer accounts has slowly increased over the past 100 years.
E
The development of sophisticated security software has rendered bank computers nearly impervious to tampering by computer hackers.
A
presumes, without providing justification, that a rise in global temperatures is harmful
B
draws a general conclusion based on a sample that is likely to be unrepresentative
C
inappropriately generalizes from facts about a specific period of time to a universal claim
D
takes for granted that the method used for gathering data was reliable
E
infers, merely from a claim that two phenomena are associated, that one phenomenon causes the other
The question stem reads: The reasoning in the scientist’s argument is most vulnerable to criticism on grounds that the argument… This is a Flaw question.
The scientist claims to have discovered that several years of atmospheric pollution during the 1500s coincided with a period of relatively high global temperatures. The scientist concludes, in this case (the period during the 1500s), that atmospheric pollution caused the global temperature to rise.
Right off the bat, we can see that the scientist has taken a correlation to mean causation. Sure atmospheric pollution coincided with higher global temperature, but perhaps the higher global temperature caused the pollution. Perhaps both were derivative effects of the same cause! As a scientist, they really should know better.
Answer Choice (A) is incorrect. The scientist has nothing to say about whether or not rising global temperatures are harmful.
Answer Choice (B) is incorrect. The scientist has not drawn a general rule. He says that atmospheric pollution caused global temperatures to rise in this case. Even if the scientist drew a general rule, we wouldn’t know whether the 1500s were likely or unlikely to be representative.
Answer Choice (C) is incorrect. (C) is very similar to (B). We can rule (C) out because the scientist did not draw a general rule.
Answer choice (D) is incorrect. Sure, we have to assume that the data methods are reliable, but that is not a flaw in reasoning.
Correct Answer Choice (E) is what we discussed. The author has assumed that the correlation between atmospheric pollution and the rising global temperature of the 1500s implies that atmospheric pollution caused the temperatures to rise.
Sabina: The label is not mistaken. After all, alphahydroxy acids also are found occurring naturally in sugarcane.