Critical Reasoning

Early in the twentieth century, Lake Konfa became very polluted. Recently fish populations have recovered as release of industrial pollutants has declined and the lake's waters have become cleaner. Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again. However, a technology for preventing leaks is being installed. Therefore, provided this technology is effective, those fears are groundless.
The argument depends on assuming which of the following?
A. Apart from development related to the pipeline, there will be no new industrial development around the lake that will create renewed pollution in its waters.
B. Other than the possibility of a leak, there is no realistic pollution threat posed to the lake by the pipeline's construction.
C. There is no reason to believe that the leak-preventing technology would be ineffective when installed in the pipeline in Lake Konfa.
D. Damage to the lake's fish populations would be the only harm that a leak of oil from the pipeline would cause.
E. The species of fish that are present in Lake Konfa now are the same as those that were in the lake before it was affected by pollution.

Confused b/w B and D . Experts please suggest

Hi,
Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again.
a technology for preventing leaks is being installed. Therefore, provided this technology is effective, those fears are groundless.
This means leaks are the only way to pollute the water. So, B is correct, IMO.
Leakage of oil would pollute water which in turn would cause damage to fish. So, D doesn't seem to be the assumption.

Hence, B
OA plz?

OA B but still not clear why D is wrong

Hi,
D. Damage to the lake's fish populations would be the only harm that a leak of oil from the pipeline would cause.
We are not concerned about what are all the damages caused by leakage. In fact leakage first causes water pollution and this water can be used for several purposes. We are only required to make sure that the water is not polluted which is the main issue and damage of fish population is just one of the consequences of water pollution.

jainrahul1985 wrote:Early in the twentieth century, Lake Konfa became very polluted. Recently fish populations have recovered as release of industrial pollutants has declined and the lake's waters have become cleaner. Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again. However, a technology for preventing leaks is being installed. Therefore, provided this technology is effective, those fears are groundless.
The argument depends on assuming which of the following?
A. Apart from development related to the pipeline, there will be no new industrial development around the lake that will create renewed pollution in its waters.
B. Other than the possibility of a leak, there is no realistic pollution threat posed to the lake by the pipeline's construction.
C. There is no reason to believe that the leak-preventing technology would be ineffective when installed in the pipeline in Lake Konfa.
D. Damage to the lake's fish populations would be the only harm that a leak of oil from the pipeline would cause.
E. The species of fish that are present in Lake Konfa now are the same as those that were in the lake before it was affected by pollution.

Confused b/w B and D . Experts please suggest

Responding to a PM. B is definitely a contender - in order to reach the conclusion that the fears of pollution are groundless based only on the fact the threat of oil leak is apparently solved, you HAVE to assume that there are no other threats for pollution around.

D is simply not an assumption that you need to make in order to reach the conclusion that the fears of pollution are groundless and there won't be any pollution. The leak will be taken care of with the technology, which we assume is effective. Therefore we do not need to concern ourselves with other forms of damage a leak would cause - as there will be no leak.

just to add-on my thought ...Choice 'D' is using the EXTREME word 'ONLY'...that could be the other reason to choose 'B' out of two choices('B' and 'D')- somewhere I read 'STAY FOCUS/STAY MODERATE' is the key to success.

jainrahul1985 wrote:Early in the twentieth century, Lake Konfa became very polluted. Recently fish populations have recovered as release of industrial pollutants has declined and the lake's waters have become cleaner. Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again. However, a technology for preventing leaks is being installed. Therefore, provided this technology is effective, those fears are groundless.
The argument depends on assuming which of the following?
A. Apart from development related to the pipeline, there will be no new industrial development around the lake that will create renewed pollution in its waters.
B. Other than the possibility of a leak, there is no realistic pollution threat posed to the lake by the pipeline's construction.
C. There is no reason to believe that the leak-preventing technology would be ineffective when installed in the pipeline in Lake Konfa.
D. Damage to the lake's fish populations would be the only harm that a leak of oil from the pipeline would cause.
E. The species of fish that are present in Lake Konfa now are the same as those that were in the lake before it was affected by pollution.

Confused b/w B and D . Experts please suggest

I too received a PM asking me to comment.

This argument exhibits a language shift.
The premise is about a non-leaking pipe.
The conclusion is about a lack of pollution.

The argument assumes that these two ideas are connected: that the construction of a NON-LEAKING pipe will guarantee a lack of pollution.

Answer choice B states this assumption: Other than the possibility of a leak, there is no realistic pollution threat posed to the lake by the pipeline's construction.

If answer choice B is reversed -- in which case, it would say that there is a HUGE pollution threat posed to the lake by the pipeline's construction -- the argument falls apart. Since the argument crumbles when B is reversed, we know that B is the necessary assumption: what must be true for the conclusion of the argument to be valid.

Answer choice D, which discusses damage from a leak, is outside the scope. The argument is about a NON-LEAKING pipe.

The correct answer is B.

Hi Mitch,

Why C is not true...??

Effectiviness of the technology is questioned when C is negated

HSPA wrote:Hi Mitch,

Why C is not true...??

Effectiviness of the technology is questioned when C is negated

The argument is about what will happen provided the technology IS effective. Since it is GIVEN that the technology is effective, answer choice C -- which discusses the effectiveness of the technology -- is outside the scope.

Hi Mitch,

Thanks for the great explanation.

Can you explain why A is incorrect.

If we reverse the answer , we get 'there will be new industrial development around the lake that
will create renewed pollution in its waters'. This will destroy the conclusion right?

I usually get stuck in answers like these and have a hard time eliminating them. Any analogy that will
help me easily bypass choices such as A?

Thanks and Regards,
Al

Alchemist14 wrote:Hi Mitch,

Thanks for the great explanation.

Can you explain why A is incorrect.

If we reverse the answer , we get 'there will be new industrial development around the lake that
will create renewed pollution in its waters'. This will destroy the conclusion right?

I usually get stuck in answers like these and have a hard time eliminating them. Any analogy that will
help me easily bypass choices such as A?

Thanks and Regards,
Al

The argument concludes that construction of a non-leaking pipeline will not cause pollution.
The negation of the correct answer must indicate that construction of a non-leaking pipeline WILL cause pollution.
A, negated:
Apart from development related to the pipeline, there will be some new industrial development around the lake will create renewed pollution in its waters.
This answer choice is about development UNRELATED TO THE PIPELINE and thus has no bearing on whether construction of the pipeline will cause pollution.
Eliminate A.