The recent construction of the chemical plant on the shores

Why not D

If there are other sources of pollutants then health decline will not be because of new plant.

The recent construction of the chemical plant on the shores of Lake Blue has introduced a new pollutant into the water: toxidil. Toxidil first works its way into the ecosystem through the underwater plant life. These plants absorb the pollutant, which is then transmitted to the local fish population when the vegetation is ingested. Fish so tainted appear healthy, but their meat, when consumed by humans, leads to serious health problems. The population living in the vicinity of Lake Blue will undoubtedly suffer a decline in health due to the new chemical plant.

Which of the following is an assumption necessary for the author's conclusion?

(A) Other pollutants are not also detrimental to human health.

(B) The fish in Lake Blue are consumed by the people who reside nearby.

(C) The first reported incidences of fish tainted with toxidil occurred in Lake Blue, and not elsewhere within Canada or the United States.

(D) Currently, the only source of toxidil in the world is the chemical plant at Lake Blue.

(E) Banning chemical processes that produce toxidil will merely cause the owners of the chemical plant to continue these same processes in secret at Lake Blue.

The question stem is asking for an assumption.

Conclusion is :
The population living in the vicinity of Lake Blue will undoubtedly suffer a decline in health due to the new chemical plant.

This is based on the assumption that people living nearby eat the fish from that lake.
If people don't eat fish from the lake they wont get the toxin into their bodies. Negating this will shatter the conclusion.

As to why d is wrong, Pay attention to the argument structure.
We dont care of there are any other sources. If there are other sources how does that affect the conclusion.
It doesn't shatter it if there are other sources of the Toxin.

Hard and fast rule to find the correct assumption.
Negate it. if negating the assumption shatters the conclusion then its the right one.

Hope i made it clear.

GMATNinja VeritasPrepKarishma

Please help with my PoE:

Conclusion: The population living in the vicinity of Lake Blue will undoubtedly suffer a decline in health due to the new chemical plant.

How does author arrive here?
A recent construction of a chemical plant introduces a pollutant T in water.
T transfers to fish wide vegetation they consume. When humans consume sick fish, they
too become sick.

So people living nearby the Lake Blue will be sick due to new chemical plant.


Negating this -> The fish in Lake Blue are NOT consumed by the people who reside nearby. Shatters the conclusion


Negate this ->Currently, there are other sources toxidil in the world than the chemical plant at Lake Blue.
Then also this WEAKENS my conclusion.Since now I can not attribute sickness of people to new chemical plant.

The recent construction of the chemical plant on the shores of Lake Blue has introduced a new pollutant into the water: toxidil. Toxidil first works its way into the ecosystem through the underwater plant life. These plants absorb the pollutant, which is then transmitted to the local fish population when the vegetation is ingested. Fish so tainted appear healthy, but their meat, when consumed by humans, leads to serious health problems. The population living in the vicinity of Lake Blue will undoubtedly suffer a decline in health due to the new chemical plant.

Which of the following is an assumption necessary for the author's conclusion?

(A) Other pollutants are not also detrimental to human health.

(B) The fish in Lake Blue are consumed by the people who reside nearby.

(C) The first reported incidences of fish tainted with toxidil occurred in Lake Blue, and not elsewhere within Canada or the United States.

(D) Currently, the only source of toxidil in the world is the chemical plant at Lake Blue.

(E) Banning chemical processes that produce toxidil will merely cause the owners of the chemical plant to continue these same processes in secret at Lake Blue.

Hi Gmat800Champ,

IMO the Answer is B. As Negating B shatters the conclusion.Remaining all options are irrelevant or Out of scope.
And please post in the correct category by mentioning the relevant source.

Thanks

+1 if this helps!

Gmat800Champ,

Merged topics. Please look before posting!

Mod Nightblade

Yes, got your point, Haven't posted for a while.

The general rule for such questions should be:
1. Eliminate all out of scope options.
2. Negate the available options and check if the conclusion still holds.

We know that we are hunting for an assumption from the question stem. The issue?: the unfortunate case of water pollution in Lake Blue. The evidence we are given describes the process by which the fish are tainted, and lets us know the detrimental effects of eating these fish. The author concludes that the chemical plant will lead to health problems among the general populace of the Lake Blue area. For the conclusion to make sense, there must be a connection between it and the evidence. We know that eating tainted fish is unhealthy, so for the people to become unhealthy, they must actually eat these fish. Now that we have a good pre-phrase, its time to scan for a match, and answer choice (B) nicely sums up what we predicted the assumption must be.

(A) introduces some out-of-scope "other pollutants", which may or may not be present in Lake Blue. Even if they were, toxidil could still further reduce the health of the people. (C) and (D) introduce irrelevant information. Meanwhile, what should or could be done about the pollution is outside the scope of the passage: the author only discusses the effects of pollution, not solutions for it, so (E) is incorrect.

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