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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.

Why isn't Option D the correct answer?

OA B

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by DavidG@VeritasPrep » Tue Oct 10, 2017 9:44 am
lheiannie07 wrote: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.

Why isn't Option D the correct answer?

OA B
Conclusion: Population in vicinity of Lake Blue will suffer health problems.
Premise: Toxidil in water; plants absorb; fish eat plants; If humans eat fish they get sick

Notice that the last piece of the premise is conditional. We don't know that humans will eat the fish. We just know that they'll get sick if they do. So if we're going to conclude that people will get sick, then we're assuming that they must have eaten the fish. The answer is B
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by DavidG@VeritasPrep » Tue Oct 10, 2017 9:46 am
Why isn't Option D the correct answer?
There's no reason to assume that the chemical plant in Lake Blue is the only source of toxidil in the world. If there are other plants in other parts of the world that produce the pollutant, the conclusion could still hold, provided that the people near Lake Blue were eating the contaminated fish.
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