Crops can be traded on the futures market before they are harvested.

hope is clear

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Oh! I am sorry. I was unaware about the rules. In fact i just read them for the first time.

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carcass

this is proposal passage
do x then Y happen
if rain is good, the crop is good and price falls.

prethink
-assumption is that there is no bad agent
- weakener, there is some bad agent
go to answer choices, look for bad agent.
- D is bad agent.

Crops can be traded on the futures market before they are harvested. If a poor corn harvest is predicted, prices of corn futures rise; if a bountiful corn harvest is predicted, prices of corn futures fall. This morning meteorologists are predicting much-needed rain for the corn-growing region starting tomorrow. Therefore, since adequate moisture is essential for the current crop’s survival, prices of corn futures will fall sharply today.

Which of the following, if true, most weakens the argument above?

Poor harvest - high prices
Good harvest - low prices

Prediction - Much needed rain for corn.
conclusion - Prices of corn will fall sharply

Weakener should weaken the conclusion. We are looking for answer choice that will give enough reason for us to doubt whether the prices can still increase even when good rain is predicted.
Something that will destroy the crops even when the rain is plentiful.

(A) Corn that does not receive adequate moisture during its critical pollination stage will not produce a bountiful harvest. - Incorrect. Kind of a strengthener.
(B) Futures prices for corn have been fluctuating more dramatically this season than last season. - Incorrect. Not concerned with prices comparison.
(C) The rain that meteorologists predicted for tomorrow is expected to extend well beyond the corn-growing region. - Incorrect. This is a trap answer. This may lead us to believe that too much rain can destroy the harvest. But the passage does not say so.
(D) Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season. - Correct. If the harvest is destroyed by disease then the prices might go up. Weakens the conclusion.
(E) Most people who trade in corn futures rarely take physical possession of the corn they trade. - Incorrect. Irrelevant.

Can someone maybe better explain this to me.

I don't think it's D because the question asked what would weaken the the argument (the argument is about rain in relation to corn growth). This answer choice merely introduces a new aspect (disease, which is not part of the argument) into the equation. If the question asked which of the following, if true, Would decrease corn production or increase corn futures? Than this would answer it. But, as it stands the choice does nothing to the argument.

I think choice A answers the question and is relevant to the argument. The argument is: you need rain for corn growth and you are expecting rain -> corn will grown -> prices of corn futures will decrease.
Choice A says corn that doesn't receive moisture during its critical pollination stage will not produce bountiful harvest.

Passage says adequate moisture is essential for current crops survival. Choice A says there is a critical stage (time) in a corn plants life and during this stage (time) if it doesn't receive moisture (rain) it won't grow. And since the rain now is "much needed" according to the passage, this indicates there wasn't much rain before, so essentially you already missed that bus, when rain was needed (at a certain stage aka time) it wasn't available.

Type- weaken
Boil it down - Met had predicted rain for corn season starting tomorrow and hence the price of corn futures will fall sharply today
Pre-thinking - some threat will hamper the corn harvest
(D) Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season. - The harvest is likely to be poor and price of corn futures will rise

Answer D

I have selected option a, my reason for selection is : If moisture at pollination stage is not attained then there will be no bountiful harvest, which means, prices will rise...

kindly explain, why my reasoning is wrong?

Option A does NOT state that corn will not attain adequate moisture. It just implies that IF corn does not attain adequate moisture level, the production will be hampered. Thus option A is a neutral fact about corn production. It does not strengthen or weaken the argument because it does not say whether the adequate moisture level will actually be attained or not. Hence option A is wrong.

D is the correct choice - This statement properly identifies information that weakens the argument.

Pre-thinking: One reason that the does not give a bountiful corn harvest!

Option D is a straight forward choice!

Premises:
meteorologists are predicting rain for the corn-growing region starting tomorrow.
If bountiful corn harvest is predicted, prices of corn futures fall.

Conclusion:
since adequate moisture is essential for the current crop’s survival, prices of corn futures will fall sharply today.

Pre-thinking - Something tells me price will not fall cause may be not a good crop. well many factors are needed to have a good crop.

The correct answer will weaken the conclusion.

D: Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season. ---- Thus, it is NOT true that a bountiful harvest is predicted, WEAKENING the conclusion that prices of corn futures will fall.

The correct answer is D.

VeritasKarishma GMATNinja

i have doubt if option d wasn't there can we say that option c can be correct by looking( since adequate moisture is essential for the current crop’s survival) here adequate may mean just sufficient required and it's been telling rain will go beyond season which may be more than required it may cause damage or we can't say because we don't know how much it is required.

The structure of the argument is as follows:

Bad harvest predicted ---> price increase
Good harvest predicted ---> price decrease
meteorologist predicts good rain ---> (good rain necessary for harvest) --> therefore, price WILL drop.

To weaken the argument, we need to show that the upcoming rain season will create problems for the corn harvest (which then depletes the corn stock and hence INCREASES the price)


(A) Corn that does not receive adequate moisture during its critical pollination stage will not produce a bountiful harvest. - the passage does not mention anything about those corn crops that do not receive adequate moisture. (A) is irrelevant for this reason and is hence incorrect. so, eliminate (A)


(B) Futures prices for corn have been fluctuating more dramatically this season than last season. - we are not interested in the fluctuation of prices; rather, we are trying to explain why the predicted rain may not be beneficial for the harvest of corn. Hence, eliminate (B)

(C) The rain that meteorologists predicted for tomorrow is expected to extend well beyond the corn-growing region. - Irrelevant since we are not interested in knowing more about the different regions that will get affected by the predicted rain. Hence, eliminate (C)


(D) Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season. - this means that the predicted rain will be accompanied by a diseases that will deplete the harvested corn stock. once this happens, the prices WILL FALL. This is exactly what would weaken the argument. Hence, (D) is the right answer.


(E) Most people who trade in corn futures rarely take physical possession of the corn they trade. - irrelevant. Hence, eliminate (E).

Much needed rain for corn is predicted from tomorrow.
Adequate moisture is essential for current crop's survival.

Conclusion: Prices of corn futures will fall sharply today (implying that bountiful crop harvest will be predicted)

What would weaken the conclusion. Note that the argument gives us that one necessary condition for a bountiful crop will be met. The conclusion says that this will lead to a bountiful crop. What will weaken this? If we say that some other necessary condition will not be met then our conclusion is weakened.

(A) Corn that does not receive adequate moisture during its critical pollination stage will not produce a bountiful harvest.

We already know that adequate moisture is necessary.

(B) Futures prices for corn have been fluctuating more dramatically this season than last season.

Irrelevant

(C) The rain that meteorologists predicted for tomorrow is expected to extend well beyond the corn-growing region.

The rain will extend beyond the corn growing region so it will cover other areas too where no corn is grown. This is irrelevant. We only need to worry about the corn growing region and we know that they will receive rain.

(D) Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season.

Now, if the prediction of corn crop getting destroyed by a disease is announced, then the price of corn futures may not fall because a bountiful crop my not be expected. So another necessary condition for bountiful crop would be 'no disease' which is not being met. Correct

(E) Most people who trade in corn futures rarely take physical possession of the corn they trade.

Irrelevant.

Answer (D)

I hope you understand why (C) cannot be the answer here is any case. It is 'region', not 'season'.
Anyway, a good CR question does not make you choose between two options with slightly different strengths - there will always be one correct answer only.

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