European green crabs are an invasive species which have

Question

European green crabs are an invasive species which have recently colonized the Northwest coast of North America, among other places. They disrupt ecosystems and prey heavily on native shellfish. However, in Europe, the population of green crabs is kept relatively low by a parasitic barnacle called Sacculina carcini. This barnacle is hardy and could likely be introduced to areas where the European green crab threatens to ruin established ecosystems.

Which of the following, if true, most strongly supports the argument that it would NOT be advisable to attempt to eliminate European green crabs from the Northwest coast of North America by introducing to the area the parasitic barnacle discussed above?

Which of the following, if true, most strongly supports the argument that it would NOT be advisable to attempt to eliminate European green crabs from the Northwest coast of North America by introducing to the area the parasitic barnacle discussed above?

A: In their native habitat, the parasites often threaten the elimination of local green crab populations.
B: European green crabs are also occasionally preyed upon by fishes, gulls and other species of crab in their native ecosystems.
C: Though the parasite may survive in North American waters, no large-scale facility for breeding and harvesting the parasites exists as of yet.
D: Many other invasive species on the Northwest coast of North America are not suitable hosts for this parasite.
E: Though the barnacle cannot reproduce inside of native shore crabs, it can still infect and kill native shore crabs.

skovinsky · Accepted Answer

Hi!

When you're not sure about the original explanation, it's very helpful for you to post the source and the explanation with which you disagree.

That said, I'm happy to comment on the question. (E) should indeed be the correct answer.

Step 1 of the Kaplan Method for CR: Identify the Question

When you have a complicated question stem, as is the case here, it's worth spending a bit of extra time to make sure you understand what the question is asking; after all, if you misinterpret the question, you're already in big trouble.

We see "Which of the following most strongly supports" and we think "strengthening". However, we want to support that course of action is "NOT... advisable". In other words, we want to weaken that course of action.

So, paraphrasing the question:

OK - that's much simpler.

Step 2 of the Kaplan Method for CR: Untangle the Stimulus

For weakening questions, we usually have to deconstruct the entire argument. However, this question is so specific that we can probably avoid doing so. We still need to read the stimulus to put the question stem in context, so let's paraphrase as we go:

Step 3 of the Kaplan Method for CR: Make a Prediction

We see that the author has a plan to fight the green crab invasion. To weaken a plan or proposal, we usually look for either an obstacle to the plan working or an undesirable side effect of the plan. So, with that prediction in mind, let's go to the last step:

Step 4 of the Kaplan Method for CR: Attack the Choices

Since we have a prediction, we go through the choices aggressively looking for a match.

(A) I'm not even sure I understand this choice (was it reproduced correctly?). However, here's the good news: it definitely doesn't match our prediction, so we can ignore it and move on.

(B) Not a reason why the plan won't work or a negative effect of the plan - move on.

(C) Not a reason why the plan won't work or a negative effect of the plan - move on.

(D) Not a reason why the plan won't work or a negative effect of the plan - move on.

(E) Ding! (E) tells us that the barnacle can kill off native species - definitely an undesirable side effect. (E) is the GMAT equivalent of  there was an old lady who swallowed a fly . Choose (E)!

metallicafan · Answer

+1 E

Between A and E. But I choose E because it is a negative effect of the proposed plan.

Nevernevergiveup · Answer

European green crabs are an invasive species which have recently colonized the Northwest coast of North America. 
They disrupt ecosystems and prey heavily on native shellfish. 
However, in Europe, the population of green crabs is kept relatively low by a parasitic barnacle called Sacculina carcini. 
This barnacle could likely be introduced to areas where the European green crab threatens to ruin established ecosystems.

Which of the following, if true, most strongly supports the argument that  it would NOT be advisable  to attempt to eliminate European green crabs from the Northwest coast of North America by introducing to the area the  parasitic barnacle  discussed above?

A. In their native habitat, the parasites often threaten the elimination of local green crab populations.
 (They keep crab population low in their native habitat but not eliminate them. Also native scenario does not affect the proposal in NA.)

B. European green crabs are also occasionally preyed upon by fishes, gulls and other species of crab in their native ecosystems.
 (This is only occasional and even this is the info regarding their native ecosystems not NA. OFS)

C. Though the parasite may survive in North American waters, no large-scale facility for breeding and harvesting the parasites exists as of yet.
 (we are not bothered about the survivial of parasite in NA waters. OFS)

D. Many other invasive species on the Northwest coast of North America are not suitable hosts for this parasite.
 (we have info regarding any other invasive species other than European green crabs as of now. OFS)

E. Though the barnacle cannot reproduce inside of native shore crabs, it can still infect and kill native shore crabs.
 (instead of green crabs we may lose shore crabs because of introducing these parasites. This indicates that the proposal may not be advisable.)

YashYashkratos · Answer

i chose E but doesn't native shore crabs mean native to barnacle's region it is inaccurate to assume the same species exists in north america?

KarishmaB · Answer

You have to answer this question:

Which of the following, if true, most strongly supports the argument that it would NOT be advisable to attempt to eliminate European green crabs from the Northwest coast of North America by introducing to the area the parasitic barnacle discussed above?

We are talking about the North American area. So if we say that though the barnacle cannot reproduce inside of native shore crabs, it can still infect and kill native shore crabs, we are talking about the native shore crabs of America. We are saying that we should not introduce the parasitic barnacle because it can infect and kill native shore crabs (along with European green crabs).

Bunuel · Answer

Knewton Official Solution:

European green crabs are an invasive species which have recently colonized the Northwest coast of North America, among other places. They disrupt ecosystems and prey heavily on native shellfish. However, in Europe, the population of green crabs is kept relatively low by a parasitic barnacle called  Sacculina carcini . This barnacle is hardy and could likely be introduced to areas where the European green crab threatens to ruin established ecosystems.
 
Which of the following, if true, most strongly supports the argument that it would NOT be advisable to attempt to eliminate European green crabs from the Northwest coast of North America by introducing to the area the parasitic barnacle discussed above?

A. In their native habitat, the parasites often threaten the elimination of local green crab populations.
B. European green crabs are also occasionally preyed upon by fishes, gulls and other species of crab in their native ecosystems.
C. Though the parasite may survive in North American waters, no large-scale facility for breeding and harvesting the parasites exists as of yet.
D. Many other invasive species on the Northwest coast of North America are not suitable hosts for this parasite.
E. Though the barnacle cannot reproduce inside of native shore crabs, it can still infect and kill native shore crabs.

What is INVASIVE species? as also hinted in the argument, a species that is not native to the location and spreads in a way to threaten the local ecosystem. This argument describes a European crab that is invading North American coastal waters. It notes that a parasite controls the populations of such crabs in Europe and suggests the parasite could be introduced to control invasive populations in North America.
 
We are asked to find a reason why it would  not  be a good idea to introduce this parasite. The correct answer should provide some reason why the parasite would be ineffective at controlling the crab population, or provide some undesirable, unconsidered effect of introducing the parasite.
 
 Choice E  notes that the parasite can "infect and kill" native shore crabs. The parasite is being introduced to protect native species; if, instead, the parasite  kills  them, the native ecosystem is not protected. Choice  E  is correct.
 
Choice A: Opposite. This choice states that the parasites often "threaten the elimination" of local crab populations in Europe. Such a statement suggests that the parasite would be highly effective in destroying the invasive green crabs in North America. This choice argues for, not against, introducing the parasite.
 
Choice B: Irrelevant. This choice states that other predators also control the population of green crabs in Europe. This might suggest that parasites  alone  may be  less  effective at controlling the green crabs than parasites AND other predators, but it does not demonstrate that parasites alone would not lower the crab population.
 
Choice C states a logistical obstacle to the plan; there is not currently a facility which can breed large numbers of the parasite. While this may make the plan  difficult to execute , it does not mean the plan is not advisable.
 
Choice D: Irrelevant. This choice suggests that other invasive species would not be affected by the parasite. This has no bearing on whether the parasite would control the population of green crabs.

Answer: E

sarthak1701 · Answer

The key to note is that we want to advise against the plan itself and not consider the possibility that the plan may not work, approach this problem as if the bacteria can be introduced without any problems but we want a reason why we should not. Options C and D are "the plan has problems" trap choices.

Ans E.

Ans E.

European green crabs are an invasive species which have

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GMAT Critical Reasoning (CR) Questions

European green crabs are an invasive species which have

Prep Toolkit

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

More than Quant/Verbal Abilities: Speed vs. Accuracy

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From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards