The chanterelle, a type of wild mushroom, grows beneath host trees suc

Question

The chanterelle, a type of wild mushroom, grows beneath host trees such as the Douglas fir, which provide it with necessary sugars. The underground filaments of chanterelles, which extract the sugars, in turn provide nutrients and water for their hosts. Because of this mutually beneficial relationship, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.

Which of the following, if true, casts the most doubt on the conclusion drawn above?

(A) The number of wild mushrooms harvested has increased in recent years.

(B) Chanterelles grow not only beneath Douglas firs but also beneath other host trees.

(C) Many types of wild mushrooms are found only in forests and cannot easily be grown elsewhere.

(D) The harvesting of wild mushrooms stimulates future growth of those mushrooms.

(E) Young Douglas fir seedlings die without the nutrients and water provided by chanterelle filaments.

ssandeepan · Accepted Answer

OA is D. 
harvesting means cutting the mushrooms. So the conslusion is cutting the mushrooms endangers the tree.

nmohindru · Answer

IMO D) .... since number of mushrooms keep on growing even when they are harvested it does not endager the tree.

E) actually supports the argument.

abhijit_sen · Answer

Premise1: C grows beneath D.
Premise2: D provides sugar to C.
Premise3: C provides water to D. 
Premise4: Relationship is mutual.
Conclusion: C beneath D seriously endangers the D.

(A) The number of wild mushrooms harvested has increased in recent years.
Does not point what happens to D because of this phenomenon, so not relavant.

(B) Chanterelles grow not only beneath Douglas firs but also beneath other host trees.
Does not point why C beneath D is bad for D.

(C) Many types of wild mushrooms are found only in forests and cannot easily be grown elsewhere.
Environment in which C grows does not explains why for D it is bad.

(D) The harvesting of wild mushrooms stimulates future growth of those mushrooms.
This may be true, however it does not attack conclusion at all on how this C and D relationship is bad for D.

(E) Young Douglas fir seedlings die without the nutrients and water provided by chanterelle filaments.
This destroys the conclusion. Conclusion says because of C and D relationship, D dies, however, this tells us because of relationship D infact survives because of relationship.

IMO E.

LM · Answer

If the harvesting of wild mushrooms stimulates future growth of those mushrooms then there is not reason to worry about the endangerement of the Douglas Fir! So "D" counters the conclusion drawn above.

GMAT TIGER · Answer

D. the passage says "harvesting mushroom endangers the tree's life". D says harvesting mushroom stimulates more mushrooms. So harvesting is not a problem.

Maryam787 · Answer

I agree that E supports the argument,,As conclusion is cutting the trees would endanger the tree,,,,We have find option which doesn't endanger the tree how come the option D is applicable??? The harvesting of wild mushrooms stimulates future growth of those mushrooms. Kindly brief it, thank you

MacFauz · Answer

The argument says that harvesting the mushrooms will endanger the tree because after being harvested, there wont be any mushrooms to provide the tree with nutrients.

Choice D says that harvesting the mushrooms would lead to further growth of mushrooms. Hence the argument's conclusion is rendered incorrect.

KarishmaB · Answer

What is the conclusion? 
"harvesting the mushroom seriously endangers these trees"

To weaken it we need to provide an explanation why harvesting the mushroom may not endanger these trees. 
We know that mushrooms and trees benefit each other. 
Option (D) tells us that harvesting of wild mushrooms stimulates future growth of those mushrooms. This means that even if you harvest the mushrooms, they will grow back and hence the beneficial relation will continue or perhaps even become better since harvesting stimulates future growth. 
This weakens the statement that harvesting the mushrooms endangers these trees.

None of the other options weaken our conclusion.

KarishmaB · Answer

(E) strengthens the conclusion, not weakens it. 
The conclusion is "harvesting the mushroom seriously endangers these trees". You could easily follow it up with option (E): "Young Douglas fir seedlings die without the nutrients and water provided by chanterelle filaments". It provides support to my conclusion that yes, harvesting the mushroom might endanger the Douglas fir trees because there seedlings will die. We need to weaken the conclusion so (E) doesn't work at all.

pkshankar · Answer

Conclusion - Harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.

We need to find a weakener i.e. something which should say that harvesting the chanterelles would in turn do greater good to the host tree by more than compensating for the loss of nutrients and water OR something which should say that even though chanterelles are providing water and nutrients but in turn are committing greater harm to the host tree. Any answer along any of these 2 lines of reasoning would be apt.
Option 'D' is the correct answer as it says that harvesting is necessary as it stimulates the growth of more such mushrooms and this is along the lines of reasoning of the 1st statement made above.

dcummins · Answer

The argument assumes that the tree is dependent on the mushrooms.

The logic of D is this - if you stop harvesting the mushrooms the mushrooms will not grow thus endangering the tree, so you need to keep harvesting the mushrooms to sustain the tree.

E is a strengthener- E validates the assumption that the trees are dependent on the mushrooms for survival, solidifying the argument. E is then obviously incorrect.

VerbalBot · Answer

Automated notice from GMAT Club VerbalBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.

The chanterelle, a type of wild mushroom, grows beneath host trees suc

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

The chanterelle, a type of wild mushroom, grows beneath host trees suc

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards