Biologists have noted reproductive abnormalities in fish that are immediately downstream of paper mills. One possible...

Joesolo on August 1, 2013


Can someone help explain to me how C is the correct answer? I was thrown off by this question. Thank you

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Naz on August 1, 2013

The conclusion of the argument is: "dioxin is unlikely to be the cause." The premise is : "fish recover normal hormone concentrations relatively quickly during occasional mill shutdowns and dioxin decomposes very slowly in the environment." We clearly have someone trying to invalidate a cause and effect relationship (dioxin causes reproductive abnormalities to the fish immediately downstream of the paper mill). The speaker is trying to explain that it is not a true cause and effect by illustrating a situation where the cause is present (dioxin stays in the environment for a long time even if the paper mill is shutdown), without the effect (the fish recover normal hormone concentrations). We are asked to weaken this argument.

Answer choice (C) does just that. When the mill shuts down, the dioxin is not being released into the area immediately downstream of the paper mill. So, even though dioxin stays in the environment for a long time, if the current carries dioxin far downstream, then soon most of the dioxin will be far downstream, so the cause is no longer present. Therefore, the fish regaining normal hormone concentrations during the mill shutdown (the effect not occurring) has no impact on the cause and effect relationship the author is trying to disprove because the cause, dioxin, is not present to detriment the fish.

I hope that helps! Let me know if you have any other questions.

nikorasu on November 14, 2017

How did you figure out that this was a cause and effect relationship?