In an attempt to produce a coffee plant that would yield beans contain

In an attempt to produce a coffee plant that would yield beans containing no caffeine, the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both. For those plants in which synthesis of the substance was blocked only in the leaves, the resulting beans contained no caffeine.

Any of the following, if true, would provide the basis for an explanation of the observed results EXCEPT:

This type of question requires an answer that fills the gap for the result to make sense completely.
There are three ways to get caffeine-free beans, by blocking synthesis of a substance that helps in caffeine production in either of the three ways :
- Blocking in the leaves
- Blocking in the beans
- Blocking in both

So there're few plants in which blocking happened in the leaves and resulting beans had no caffeine. What might explain this.??
Only C and E are contenders.

A. In coffee plants, the substance is synthesized only in the leaves and then moves to the beans, where the initial stages of caffeine production take place. - WRONG. This helps explain. Synthesis in leaves ----> substance moves then to beans. Now, Synthesis in leaves ----> substance moves then to beans.

B. In coffee plants, the last stage of caffeine production takes place in the beans using a compound that is produced only in the leaves by the substance. - WRONG. Only leaves produce a compound ---> Using that compound caffeine production takes place in the beans. Now, leaves produce a compound ---> Using that compound caffeine production takes place in the beans.

C. In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance. - CORRECT. caffeine production happens only in the beans -----> From here two things happen:
1. - either another substance is synthesized only in leaves which then gets blocked as per question
- OR it is not synthesized
2. - or it does not depend on blocked substances.

So, either's there's a blockage or non OR its happening doesn't depend. The caffeine is not there in the beans in either case.

D. In coffee plants, caffeine production takes place only in the leaves, but the caffeine then moves to the beans. - WRONG. Don't know what 'BUT' is doing actually here. Only leaves produce caffeine ----> Then caffeine moves to beans. Now, leaves produce caffeine ----> Then caffeine moves to beans.

E. Caffeine was produced in the beans of the modified coffee plants, but all of it moved to the leaves, which normally produce their own caffeine. - WRONG. This is cruel one. First caffeine is produced in beans ---> all caffeine moves to leaves ----> leaves produce own caffeine. Now, First caffeine is produced in beans ---> all caffeine moves to leaves ----> leaves produce own caffeine. Thus, no caffeine in beans as everything kept on moving to leaves which don't produce caffeine now.

Answer C.

I still don't get why C is the answer.
If the initial stages of caffeine production in the beans is blocked, how would the the production of caffeine even reach the later stage (where the other substance comes in)?

From the argument, it is evident that for the beans to have coffee, the substance was synthesized in the leaves. In essence, presence of the substance in the leaves is a necessary condition for the plant to yield caffeine. Any choice that does not bring in this fact cannot explain the result.

A) In coffee plants, the substance is synthesized only in the leaves and then moves to the beans, where the initial stages of caffeine production take place. Yes, this choice talks about synthesis in leaves as a necessity. Since this choice explains the argument, this choice cannot be the answer.

B) In coffee plants, the last stage of caffeine production takes place in the beans using a compound that is produced only in the leaves by the substance. This choice also attributes the source of caffeine to the leaves just as choice A does. Since this choice explains the argument, this choice cannot be the answer.

C)In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance. This choice does not meet the necessary condition we are looking for! It says that the ultimately the production of caffeine although in the leaves is independent of the substance! Why? If this statement were true, then blocking the substance cannot explain the absence of caffeine since this choice confirms the substance does not play a role in caffeine production. Hence, this choice does not explain the argument. (C) looks promising.

D) In coffee plants, caffeine production takes place only in the leaves, but the caffeine then moves to the beans. same as choice (A) and hence cannot be the answer.

E) Caffeine was produced in the beans of the modified coffee plants, but all of it moved to the leaves, which normally produce their own caffeine. This choice says that leaves produce their own caffeine so it explains our argument. Note that beans may or may not produce caffeine that does not impact our argument. Since this choice explains the argument, this choice cannot be the answer.

Yes exactly you are correct!
The question demands the right option as the one that does not explain the scenario where synthesis blocked in leaves produces no caffeine but when blocked in beans or in both is produces.
And this option does not explain why this happens
Hence the correct answer choice!

THANKYOU MERC

(A) - since the substance is essential to caffeine production, and is only produced in the leaves, blocking it in the leaves makes caffeine production impossible.

(B) - respecting the essentials, identical to (A). The only (irrelevant) difference is which stage of caffeine production is impacted.

(C) - on the basis of (C), the question of where the caffeine ends up is left unaddressed, and the initial stages of caffeine production are not prevented from occurring, because the initial stages take place in the beans, which still contain the substance. Furthermore, (C) gives us no reason to think the later stages of caffeine production are impacted by the absence of the substance in the leaves.

(D) - the substance is essential to caffeine production, which takes place only in the leaves. Therefore, if the substance is blocked, no caffein production will take place.

(E) - caffeine production took place in the beans, but the caffeine moved to the leaves, meaning the beans no longer contain caffeine.

Dear Experts

please help with option e and c. I selected E as i found the role of blocking synthesizer in leaves at initial stage stands null and void.

Thanks and Regards

The idea of (E) is that, normally, leaves have the substance and make their own caffeine, but, in this case, the substance was blocked in the leaves. Because the substance was blocked in the leaves, the leaves didn't manufacture their own caffeine. As a result, caffeine that was manufactured in the beans moved to the leaves, leaving the beans with none.

Of course, that this would occur explains why blocking the substance in the leaves results in the beans' containing no caffeine.

(C), on the other hand does not help to explain why the beans contain no caffeine. (C) says that the part of the caffeine production process that involves the leaves does not involve the blocked substance, leaving us still wondering why blocking the substance in the leaves results in the beans' containing no caffeine.

took me almost 3 min to solve this .



In an attempt to produce a coffee plant that would yield beans containing no caffeine, the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both. For those plants in which synthesis of the substance was blocked only in the leaves, the resulting beans contained no caffeine.

Any of the following, if true, would provide the basis for an explanation of the observed results EXCEPT:


A. In coffee plants, the substance is synthesized only in the leaves and then moves to the beans, where the initial stages of caffeine production take place.

-- This helps to explain why beans have no caffeine . Since the caffeine is created only in leaves and in leaves the substance was blocked .

B. In coffee plants, the last stage of caffeine production takes place in the beans using a compound that is produced only in the leaves by the substance.

-- This helps to explain why beans have no caffeine . Since the caffeine production is dependent on leaves and in leaves the substance was blocked .


C. In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance.
-- This is the correct choice .. This choice doesn't help in explaining why there is no caffeine in the beans . Since initial stages of caffeine production take place only in the beans and later stages of caffeine production doesn't depend on the blocked contents. So there must be some other reason .

D. In coffee plants, caffeine production takes place only in the leaves, but the caffeine then moves to the beans.

-- This helps to explain why beans have no caffeine . Since the caffeine is created only in leaves and in leaves the substance was blocked .


E. Caffeine was produced in the beans of the modified coffee plants, but all of it moved to the leaves, which normally produce their own caffeine.
-- This helps to explain why beans have no caffeine . Since the caffeine is created in beans in modified plants and all caffeine moved to leaves ..(By some mechanism ) .



You may hit Kudos if the reasoning helps .

MartyTargetTestPrep GMATNinja VeritasKarishma
I got the answer right.
But I wasted a lot of time in my initial reading of the question stem.
It looks like an incomplete thought.
Which of the two things is being said here?
1) in the other two experiments (i.e where the substance was blocked in (beans only) and (in beans and leaves)).
In both the experiments there was caffeine in the beans.
OR
2) this is an incomplete thought and they have not given any further information on the results of the other two experiments.

Thanks VeritasKarishma for a detailed explanation and for clearing the confusion.

Nice explanation MartyTargetTestPrep

In an attempt to produce a coffee plant that would yield beans containing no caffeine, the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both. For those plants in which synthesis of the substance was blocked only in the leaves, the resulting beans contained no caffeine.

Any of the following, if true, would provide the basis for an explanation of the observed results EXCEPT:

P : when synthesis was blocked only in the leaves, the resulting beans contained no caffeine
WHY???

A. In coffee plants, the substance is synthesized only in the leaves and then moves to the beans, where the initial stages of caffeine production take place.
-> synthesis in the leaves is blocked -> moving to the beans where the initial stages of caffeine is produced becomes unavailable.

B. In coffee plants, the last stage of caffeine production takes place in the beans using a compound that is produced only in the leaves by the substance.
-> compound produced in the leaves is blocked -> no caffeine

C. In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance.
-> Correct, if the later procedure is not dependent to the blocked substance, no reason to presume no caffeine

D. In coffee plants, caffeine production takes place only in the leaves, but the caffeine then moves to the beans.
-> caffeine produced in the leaves cannot move to beans.

E. Caffeine was produced in the beans of the modified coffee plants, but all of it moved to the leaves, which normally produce their own caffeine.
-> caffeine produced in the beans moved to the leaves, meaning no caffeine.

How does E resolve the paradox in this case? I marked C as it specifically mentioned that caffeine production does not depend on the blocked substance but I am still not sure if E does resolve the discrepancy in the argument

According to the passage, the synthesis of the substance that leads to caffeine production was blocked only in the leaves, but the beans did not contain caffeine. (E) tells us that the caffeine was produced in the beans (because the synthesis that would allow production was blocked in the leaves), but all of the caffeine then moved to the leaves. If that’s true, then it makes sense that there would be no caffeine in the beans.

So (E) explains the results, and we can eliminate it.

I hope that helps!

Ahh.. What a cruel question!
I am not sure whether my understanding is correct, but here it is:

In an attempt to produce a coffee plant that would yield beans containing no caffeine, the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both. For those plants in which synthesis of the substance was blocked only in the leaves, the resulting beans contained no caffeine.


ARE WE TOLD WHETHER THE PLANTS IN WHICH A SUBSTANCE WAS BLOCKED IN BEANS AND IN BOTH LEAVES AND BEANS HAD / DIDN'T HAVE CAFFEINE LATER? NO!!!! I THINK THIS IS THE CATCH HERE.

A lot of us will try to find an answer that satisfies the following two conditions:
1. substance blocked in leaves
2. Substance blocked in beans and leaves
Because our logic leads us to believe that if the substance was blocked in leaves and it resulted in no caffeine, then the plants in which the substance was blocked in both leaves and beans will also have no caffeine.
And I suppose this is the mistake the test makers want us to make!
We AREN'T told anything about the other two combinations, so there is no need to bother about those combos!


Any of the following, if true, would provide the basis for an explanation of the observed results EXCEPT:

Option C is the clear winner!

C. In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance.
- This doesn't explain the result that was obtained by blocking the substance in leaves only!

Passage Analysis

In an attempt to produce a coffee plant that would yield beans containing no caffeine,
The purpose of an experiment is to produce a coffee plant that can provide coffee beans without the substance caffeine.

the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both.
There is a substance that is vital in the first stage of producing caffeine. Let us call it X.
The making of this substance X was blocked in 3 sets of plants.
In one set it was blocked only in the beans, in the second only in the leaves and in the third set in both leaves and beans.

For those plants in which synthesis of the substance was blocked only in the leaves, the resulting beans contained no caffeine.
We are given the result of only the set where the formation of X was blocked in leaves alone.
For them, the resulting beans contained no caffeine.

Question Stem

Any of the following, if true, would provide the basis for an explanation of the observed results EXCEPT:

This is a paradox question of another type. Four of the choices are explanations that can be given to explain the result, but one is not. We need to identify the unsuitable explanation.

Prethinking

The loophole in this question is that we are not given the results of what happens when the substance X formation is blocked in just beans or both beans and leaves. All we know is that blocking X in the leaves leads to non-caffeinated beans. It could be possible that all three sets of plants gave non caffeinated beans, two of the sets gave non caffeinated beans (out of them, one is definitely ‘only leaves’ set) Or only one set gave non caffeinated beans (only leaves set). What we need to find is which of the given explanation does not provide and explanation for the ‘only leaves’ set giving non caffeinated beans.

Eg: 1. Complete production of caffeine happens in the beans and not the leaves. Then blocking X in “only leaves” should have no impact on caffeine production. This cannot explain the result.

2. Initial production of caffeine happens in the beans, and the leaves play a role only in a later part where the blocked substance has no role. If the blocked substance has no role at this stage of the caffeine creation process, then blocking X in “only leaves should have no impact on caffeine production. This cannot explain the result.

3. There are other parts of the coffee plant where the substance can be passed to the leaves where initial stages of caffeine production happens. Even if X formation is blocked in leaves, X can still be produced and reach the leaves for caffeine creation. Then blocking X in “only leaves” should have no impact on caffeine production. This cannot explain the result.

Option Analysis

A. In coffee plants, the substance is synthesized only in the leaves and then moves to the beans, where the initial stages of caffeine production take place.
INCORRECT

If the substance X is synthesized only in the leaves and this production is blocked, then caffeine cannot be produced in the beans. Hence this is a correct explanation. Therefore, this cannot be the answer.

B. In coffee plants, the last stage of caffeine production takes place in the beans using a compound that is produced only in the leaves by the substance.
INCORRECT
This option says in the last stage of production of caffeine, a substance produced by X is necessary, in the leaves. If X production in the leaves is blocked this cannot lead to caffeine production. Hence this is also a correct explanation and thus a wrong answer choice.

C. In coffee plants, the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance.
CORRECT
If initial stage of production takes place only in the beans, blocking X formation in leaves only has no impact. It is also mentioned that later stages do not depend on X. Thus, if this statement is true, it should not give the provided result. Hence this is the wrong explanation and thus the right answer choice. It is in line with explanation 2.

D. In coffee plants, caffeine production takes place only in the leaves, but the caffeine then moves to the beans.
INCORRECT
If caffeine production takes place in the leaves, then blocking X can make an impact. Hence this is a proper explanation and an incorrect choice.

E. Caffeine was produced in the beans of the modified coffee plants, but all of it moved to the leaves, which normally produce their own caffeine.
INCORRECT
The option says that when the leaves were denied production of their own caffeine by blocking X formation, the caffeine that was formed in the beans all moved to the leaves, there by decaffeinating the beans. This is also a valid explanation for blocking X in the leaves leading to beans without caffeine. Hence it cannot be the correct answer choice.

It's really between C and E.

We're told that the synthesis of a substance essential for caffeine production was blocked either in the beans, in the leaves, or both.

In Choice E, we're told caffeine was produced in the beans, but all of the caffeine moved to the leaves. From this we can conclude:

- The synthesis of the substances blocked caffeine production in the leaves
- The beans no longer have caffeine (as the caffeine moved to the leaves)
- As a result, we have no caffeine in the beans & caffeine in the leaves (from the move).

Choice E can be eliminated.

In Choice C, we're told the initial caffeine production takes place only in beans, but later caffeine production depends on another substance (not dependent on the blocked substance). So if we have another substance that produces caffeine, the observed results would be strange. C is the answer.