- Mon May 18, 2020 12:06 am
#75529
Hi margidag! Let's walk through this one.
This is a Strengthen question.
Like all Strengthen questions, we want to identify the conclusion, identify the premises, find the gap between the conclusion and the premises, Pre-Phrase an answer that will help us "smooth over" the gap, and then find the answer choice that best matches our Pre-Phrase.
The conclusion here is that "it is likely that the higher death rate among the Baltic seals was due to the higher levels of pollutants in their blood."
The premises are that
- Twice as many Baltic seals died from viral infections than Scottish seals
- The Baltic seals had much higher levels of pollutants in their blood than the Scottish seals
- Pollutants impair marine animals' ability to fight off viral infections
Does the conclusion follow 100% logically from the premises? Or is there a gap in how the conclusion is drawn from the premises? Again, our conclusion here is that the pollutants caused the high death rate. The use of cause and effect reasoning is always a gap. In other words, any conclusion that determines that one thing exclusively caused a second thing is inherently making an incorrect leap of logic (we've all heard the phrase "correlation does not imply causation"). So our gap here is that the conclusion just assumes that pollutants were the cause that led to the effect of the higher death rate.
We want to Strengthen the gap of that causal relationship. In the PowerScore Bibles / Lesson Books, it walks through the 5 ways to Weaken a Causal relationship. They are: find an alternate cause, show that when the cause occurs the effect does not, show that when the effect occurs the cause does not, show the relationship is reversed, or show that a statistical problem exists with the data. To Strengthen a Causal relationship, we do want to do the opposite: we rule out an alternate cause, show that when the effect did not occur the cause did not occur, show that when the cause occurs the effect occurs, rule out the possibility that the relationship is reversed, or strengthen the data. So our Pre-Phrase here is looking for an answer choice that does one of those 5 things. For example, an answer choice that rules out an alternate cause might say: "Diet can affect a seal's ability to fight off infection; Scottish seals and Baltic seals have identical diets" Onto the Answer Choices.
Answer Choice (A): This uses none of the 5 methods above to bolster the causal argument that pollutants caused the higher death rate.
Answer Choice (B): This would be a good answer if it wasn't for the word "Scottish" in there. Our causal relationship is regarding the Baltic seals, so this doesn't really help us.
Answer Choice (C): This answer choice is irrelevant; variance in pollutant levels among the Baltic seals doesn't affect the causal relationship.
Answer Choice (D): If anything, this probably weakens the argument. It suggests an alternate cause: it is not the higher levels of pollutants in the Baltic seals, but maybe it is the different type of pollutants that accounts for the higher death rate.
Answer Choice (E): This is the correct answer. It tells us that among other marine mammals, being in the higher pollutants of the Baltic correlated with the higher death rate from viral infections. So it strengthens the argument by employing one of the 5 techniques above - specifically by showing another example of the cause occurring and then the effect occurring.
Hope that helps!
Thanks!