Rye sown in the fall and plowed into the soil in early spring leaves

I believe the answer is D.

A The argument does consider the minor crops

B Does talk about an alternative with synthetic herbicide

C Does distinguish between rye and synthetic

D Looks the best to me. The argument is very harsh on rye, " play no part". There could be a part rye could play if rye and synthetic herbicide is used together

E Irrelevant to the dicussion

As usual, a good first step is to start with the conclusion: plowing rye into the soil can play no part in effective weed control for major agricultural crops.

Next, make sure you understand the structure of the argument leading up to that conclusion. Otherwise, how will you be able to determine the vulnerability of that argument?

• First, we are told that "rye sown in the fall and plowed into the soil in early spring leaves a residue that is highly effective at controlling broad-leaved weeds." - Okay, so if you sow rye in the fall and plow it into the soil in early spring, that should help you control broad-leaved weeds.
• Unfortunately, that highly-effective weed control will only last for about forty-five days.
• "No major agricultural crop matures from seed in as little as forty-five days" - Thus, the amount of time the weed control remains effective is LESS than the amount of time it takes for a crop to mature from seed. And since you can't simply "reapply" the residue from the rye, you cannot extend that 45-day effective period. This is evidence that sowing and plowing rye might not help protect your crops from broad-leaved weeds after all.
• Unlike the rye residue that cannot simply be reapplied, synthetic herbicides CAN be reapplied as the crop grows. This fact seems to suggest that using synthetic herbicides is a more effective option than using rye residue. Thus, the author concludes that plowing rye into the soil can play no part in effective weed control for major agricultural crops.

This is what we mean when we talk about "How structural thinking can help" with CR questions (see the Ultimate CR Guide for Beginners for more details). The author presents a highly effective method for controlling broad-leaved weeds, presents a major drawback to that method, and then presents an alternative method that has the same drawback but that can be used repeatedly to address that drawback.

We've identified the conclusion and understand how the author arrived at that conclusion. NOW you can look at the question and analyze each answer choice. How might someone object to this argument? What is a major weakness in the argument? Which answer choice best completes this sentence: "The argument fails to ______."? See if that preliminary analysis helps you with the answer choices.

Good luck!
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Answer is D. Explanation: Author totally rejects rye as a means to control weeds ignoring the fact that it can be very effective for first 45 days of a crop cycle which may then followed by synthetic herbisides. This proves others conclusion is incorrect

My take:
In order to weaken the conclusion "for major agricultural crops, plowing rye into the soil can play no part in effective weed control", we can show that the rye actually can contribute to the crop by combining the two weed-control methods: rye and synthetic herbicides. D shows this.
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The conclusion states that : plowing rye into the soil can play no part in effective weed control.
the answer should be D because plowing rye can be used for 45 days and after that synhetic herbicides can be used once the crop grows.Hece when the two weed control method will work

hello, what is the most effective method and what are steps of the method to solve such kind of question?

It is because I completely get lost while finding the answer.

I understand that there has been no discussion around minor crops in the argument. However, when I was pre-thinking for suitable objections that the argument is vulnerable to, the idea of minor crops came to my mind. I still think it is a relevant option, may be not the ???most??? vulnerable one. Can any expert please reply on this post? and explain why option A is wrong and D is the most suitable one. What category of CR questions does this fall into? It does not seem like a weaken CR type. Thanks you so much guys.

(A) consider that there might be minor, quick-growing crops that do mature in forty-five days or less
- Not about minor crops so not valid
(B) identify any alternative method of weed control that could be used instead of the method it rejects
irrelevant to the discussion
(C) distinguish among the various kinds of synthetic herbicides
irrelevant to the discussion
(D) allow for the possibility of combining the two weed-control methods it mentions
this makes sense as the author has failed to consider this and discard the role of plowing rye
(E) allow for the possibility that plants other than rye, handled the same way, might have the same effect
out of scope

Let’s consider the prompt first:


This question is actually an excellent example of why rigidly categorizing CR questions into "types" may not necessarily be helpful. The test writers can come up with a theoretically infinite number of questions, but all questions are designed to test the same underlying logic and reasoning skills, no matter what “category” a particular question may fall into. This question essentially asks how someone could OBJECT to the argument, and more specifically, what that person would say the argument FAILS to consider.

With that in mind, here’s (A):


Borrowing from my earlier post, “the author concludes that plowing rye into the soil can play no part in effective weed control for major agricultural crops.” Because the author specifies that his/her conclusion ONLY applies to major agricultural crops, whether rye is effective on minor crops has no bearing on the argument. It could be true that rye is highly effective on minor crops, but that does not impact the author’s conclusion that rye is ineffective on major crops. Because the author specifically limits his/her conclusion to weed control of major crops, we can't say that the argument FAILS TO CONSIDER minor crops. So, an objection on the grounds provided in (A) doesn't actually poke a legitimate hole in the argument. Eliminate (A).

And here’s (D):


The author concluded that plowing rye can play NO PART in weed control for major crops. But combining the two weed-control methods would allow farmers to use rye first, and then synthetic herbicides for the duration of the crop-maturation process. If that is the case, then plowing rye can play SOME PART in effective weed-control for major crops. The author failed to consider this possibility in his/her argument. Therefore, (D) is correct.

I hope that helps!
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Hi GMATNinja,

A quick clarification - do you mean "MORE" in the 3rd bullet point above? (and typed "LESS" by mistake) or am I understanding your point incorrectly?

"No major agricultural crop matures from seed in as little as forty-five days" - Thus, the amount of time it takes for a crop to mature from seed is LESS than the amount of time the weed control remains effective. And since you can't simply "reapply" the residue from the rye, you cannot extend that 45-day effective period. This is evidence that sowing and plowing rye might not help protect your crops from broad-leaved weeds after all.

Thanks

Yes, that was in fact a typo (that has now been fixed)... thanks for letting us know!! Please eat a few extra dosas for me.
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Solution

Passage Analysis

Rye sown in the fall and plowed into the soil in early spring leaves a residue that is highly effective at controlling broad-leaved weeds,
A crop called rye can be very effective in controlling broad-leaved weeds when its residue is left in the soil after sowing it in the fall season and plowed in early spring season.

but unfortunately for only about forty-five days.
But this type of control works for only around 45 days.

No major agricultural crop matures from seed in as little as forty-five days.
This time period of 45 days is not enough for any major agricultural crop to grow enough from the seed condition.

Synthetic herbicides, on the other hand, although not any longer-lasting, can be reapplied as the crop grows.
Artificial herbicides have the advantage of re-applicability even though their effect also lasts only that long.

Clearly, therefore, for major agricultural crops, plowing rye into the soil can play no part in effective weed control.
The author concludes that, in the case of major agricultural crops, the rye method cannot play any part at all in effective weed control. This is the main conclusion


Question Stem
The argument is most vulnerable to the objection that it fails to
The flaw in this argument is that it misses one key aspect while forming the conclusion. Identify the same.

Prethinking

The problem with the rye method is that it can be done only once in the beginning and cannot be repeated for as long as it takes. So the author straight away jumps into the conclusion that it can play no role at all in weed control of major crops. Sure, we do not have to consider the case of other crops since the conclusion does not demand it. But why do we have to negate the possibility of partial usage of the rye method? May be the initial period of weed control can be through this method and once it wears off, synthetic herbicides can aid the crops! The author can be noted to be unnecessarily declining this possibility. That happens to be the flaw in this argument.

Option Analysis

(A) consider that there might be minor, quick-growing crops that do mature in forty-five days or less
As the conclusion deals only with the major crops, this option is irrelevant.

(B) identify any alternative method of weed control that could be used instead of the method it rejects
The conclusion does not demand any alternative for the rye method. It only says rye method cannot be used at all. Hence irrelevant.

(C) distinguish among the various kinds of synthetic herbicides
That step is irrelevant as the conclusion does not speak of using herbicides; it only speaks of not using the rye method.

(D) allow for the possibility of combining the two weed-control methods it mentions
This option is in line with our prethought solution. Hence this is the correct answer.

(E) allow for the possibility that plants other than rye, handled the same way, might have the same effect.
Same as B. The conclusion is not affected by any other method than the rye method.

The correct answer is D.
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Alright. So it's a flaw question (notice that the stem doesn't have the "if true" language)



Alright so in their words:
1. Rye used in a particular way is highly effective at controlling certain types of weed but only for 45 days
2. No major agricultural crop matures in 45 days. (A lot of modifiers- no, major, agricultural! As GMATNinja says, these modifiers should make your ears stand)
3. SH are longer lasting since they can be reapplied *as* crop grows. (Okay so this addresses a problem implicitly mentioned previously - Rye needs to be sown in fall and then plowed in early sprint - and so we cannot have any other crop growing at that time. On the other hand SH enables us to do so. Great!)
4. Conclusion: *for major agricultural crops* plowing Rye can play *no* part in *effective weed control*. (Woah! A bit more extreme conclusion. Just because something takes time, doesn't mean it's not effective but let us avoid getting into our words now)



Sure it would be nice if they considered but this statement doesn't weaken the conclusion that Rye can play *no* part.


Well, it did identify a method! This is out.


Distinguishing among various kinds of herbicides will not help shed more light on the effectiveness of Rye. This is out too.


Hmm. This is very vague so need to give it some thought. The two methods it mentions are: Rye and SH. Now if they are combined to be something even more effective, then we cannot dismiss that Rye can play no part, right? Of course, it may be the case that things get worse when we combine it but, hey, before dismissing it altogether this argument didn't even consider all possibilities and this is taking a note. Let's keep it.


Again, it would be nice if they told that but this is not a flaw in the way this argument reaches the conclusion.

D is your answer.

Hello,

I was stuck between C and D , eventually chose C . Can you kindly explain the difference ? My reasoning:
A- Wrong: as it is mentioned in the question : " No major agricultural crop matures from seed in as little as forty-five days" so as if we are contradicting the premise here. So A is out ( is my reasoning correct ? )
B- There is an alternative mentioned : synthetic
C- What if we had another synthetic herbicide that might be the best one and indeed can be considered as the one and only to use therefore plowing rye will have no part in effective weed contrl ?
D- I was also considering this option too.
E- Out of scope.

Thanks,

The argument claims that plowing rye into the soil cannot play a part in effective weed control for major agricultural crops because the residue only lasts for 45 days, whereas synthetic herbicides can be reapplied as the crop grows. To strengthen the argument, we need to find an objection that the argument fails to address. Let's evaluate the options:

(A) consider that there might be minor, quick-growing crops that do mature in forty-five days or less
This objection suggests that there might be crops that mature within 45 days or less, making the residue from plowed rye effective for weed control. Since the argument focuses on major agricultural crops, the objection is not relevant and does not weaken the argument.

(B) identify any alternative method of weed control that could be used instead of the method it rejects
This objection suggests that there might be alternative methods of weed control that can be used instead of plowing rye into the soil. It points out a potential flaw in the argument by not considering other effective weed control methods.

(C) distinguish among the various kinds of synthetic herbicides
This objection suggests that the argument fails to distinguish between different types of synthetic herbicides, which could have varying levels of effectiveness or longevity. While this is a valid point, it does not directly weaken the argument.

(D) allow for the possibility of combining the two weed-control methods it mentions
This objection suggests that combining the residue from plowed rye with synthetic herbicides might provide more effective and longer-lasting weed control. It points out a limitation in the argument by not considering the possibility of using both methods together.

(E) allow for the possibility that plants other than rye, handled the same way, might have the same effect.
This objection suggests that other plants, similar to rye and treated in the same manner, might also have a similar effect in controlling weeds. It highlights a limitation in the argument by not considering alternative crops with similar weed control properties.

Based on the analysis, the objection that most weakens the argument is (D) allow for the possibility of combining the two weed-control methods it mentions. The argument only considers the individual effectiveness of plowing rye or using synthetic herbicides, without considering the possibility of combining both methods for more comprehensive weed control.