Critical Reasoning

After the recent court rulings, commercial shark fishing and shark hunting will resume in Diamond Bay. Many citizens of the communities around the bay have hailed this move, believing that a decrease in sharks will lead to an increase in all smaller fish, including the endangered Green-Gilled Silverfish, whose only ecosystem is within Diamond Bay. Ecologists, though, disagree, pointing out that a decrease in sharks will lead to a surge in Sea Lions, which are the principal predator of the Green-Gilled Silverfish.

In the argument given, the two portions in boldface play which of the following roles?

A) The first provides support for conclusion of the argument; the second states that conclusion.
B) The first describes evidence that has been taken as supporting a conclusion; the second states a contrary conclusion that is the main conclusion of the argument.
C) The first is an opinion that the argument opposes; the second is evidence inconsistent with the conclusion of the argument.
D) The first describes the circumstances that the argument as a whole seeks to explain; the second gives the explanation that the argument seeks to establish
E) The first describes the circumstances that the argument as a whole seeks to explain; the second provides evidence in support of the explanation that the argument seeks to establish.

Source: Magoosh

OA: B

Where is the main conclusion. According to Magoosh,the main conclusion is the ecologists's believing? As far as I learn in CR, main conclusion is the author's view? Dos author's view is considered the ecologists view.

Mo2men wrote:After the recent court rulings, commercial shark fishing and shark hunting will resume in Diamond Bay. Many citizens of the communities around the bay have hailed this move, believing that a decrease in sharks will lead to an increase in all smaller fish, including the endangered Green-Gilled Silverfish, whose only ecosystem is within Diamond Bay. Ecologists, though, disagree, pointing out that a decrease in sharks will lead to a surge in Sea Lions, which are the principal predator of the Green-Gilled Silverfish.

In the argument given, the two portions in boldface play which of the following roles?

A) The first provides support for conclusion of the argument; the second states that conclusion.
B) The first describes evidence that has been taken as supporting a conclusion; the second states a contrary conclusion that is the main conclusion of the argument.
C) The first is an opinion that the argument opposes; the second is evidence inconsistent with the conclusion of the argument.
D) The first describes the circumstances that the argument as a whole seeks to explain; the second gives the explanation that the argument seeks to establish
E) The first describes the circumstances that the argument as a whole seeks to explain; the second provides evidence in support of the explanation that the argument seeks to establish.

Many BF CRs are structured as follows:
Many people believe that X is true.
They are wrong.
Generally, the main conclusion of the argument will be the statement in blue.

In the passage above:
Many citizens believe that a decrease in sharks will lead to an increase in all smaller fish, including the endangered Green-Gilled Silverfish.
Ecologists disagree.
Here, the main conclusion of the argument is the statement in blue.
Since the ecologists DISAGREE with the citizens, the main conclusion is that a decrease in sharks will NOT lead to an increase in all smaller fish.

BF1 is a PREMISE serving to support the conclusion of the citizens.
BF2 is the main conclusion: that that a decrease in sharks will NOT lead to an increase in all smaller fish but will lead to a surge in Sea Lions, which are the principal predator of the Green-Gilled Silverfish.

Only B correctly describes how each BF functions:
The first describes evidence that has been taken as supporting a conclusion (the conclusion of the citizens); the second states a contrary conclusion that is the main conclusion of the argument (the conclusion of the ecologists, who hold that the citizens are WRONG).

The correct answer is B.

GMATGuruNY wrote: In the passage above:
Many citizens believe that a decrease in sharks will lead to an increase in all smaller fish, including the endangered Green-Gilled Silverfish.
Ecologists disagree.
Here, the main conclusion of the argument is the statement in blue.
Since the ecologists DISAGREE with the citizens, the main conclusion is that a decrease in sharks will NOT lead to an increase in all smaller fish.

BF1 is a PREMISE serving to support the conclusion of the citizens.
BF2 is the main conclusion: that that a decrease in sharks will NOT lead to an increase in all smaller fish but will lead to a surge in Sea Lions, which are the principal predator of the Green-Gilled Silverfish.

Dear Mitch,

Thanks for help.

Does the ecologists' conclusion qualify to be the author's main conclusion? There is no clear voice of author's conclusion. I assume it has been inferred to stemmed from ecologist's conclusion.

Am I right??

Mo2men wrote: Dear Mitch,

Thanks for help.

Does the ecologists' conclusion qualify to be the author's main conclusion? There is no clear voice of author's conclusion. I assume it has been inferred to stemmed from ecologist's conclusion.

Am I right??

The CR above does not seem reflective of an official BF CR.
Generally, when the main conclusion in an official BF CR is attributed to a specific group, that group is clearly identified as the author of the passage.
On the GMAT, the CR above would probably appear as follows:

Ecologists: After the recent court rulings, commercial shark fishing and shark hunting will resume in Diamond Bay. Many citizens of the communities around the bay have hailed this move, believing that a decrease in sharks will lead to an increase in all smaller fish, including the endangered Green-Gilled Silverfish, whose only ecosystem is within Diamond Bay. These citizens are mistaken, however, since a decrease in sharks will lead to a surge in Sea Lions, which are the principal predator of the Green-Gilled Silverfish.

In the ecologists' argument, the two portions in boldface play which of the following roles?

The OA would likely read as follows:
The first describes evidence that has been taken as supporting a conclusion that the ecologists oppose; the second states a contrary conclusion that is the ecologists' main conclusion.

Mo2men wrote:Does the ecologists' conclusion qualify to be the author's main conclusion? There is no clear voice of author's conclusion. I assume it has been inferred to stemmed from ecologist's conclusion.

I think that's a great point.

GMATGuruNY wrote:The GMAT would likely deem BF2 the main conclusion not of the author but of the passage.

Don't you think that it's more likely that the GMAT would specify that the argument is being made by ecologists, and that the correct option should be chosen keeping that in mind?

AjiteshArun wrote:Don't you think that it's more likely that the GMAT would specify that the argument is being made by ecologists, and that the correct option should be chosen keeping that in mind?

Yes.
Please revisit my second post above.
I've edited it to illustrate how the CR above would likely appear on the GMAT.