Logical Reasoning

PT18 · S4 · Q14 In 1980 there was growing concern

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In 1980 there was growing concern that the protective ozone layer over the Antarctic might be decreasing and thereby allowing so much harmful ultraviolet radiation to reach the Earth that polar marine life would be damaged.

Conclusion

Don't worry that the ozone layer is decreasing and thereby allowing lots of harmful UV radiation to reach Earth, potentially to the detriment of polar marine animals.

Evidence

Global atmospheric ozone levels remain constant.

Evaluate / Goal

Given that global ozone levels remain constant

How could we argue we should worry that the ozone layer is decreasing and allowing UV to damage polar marine life?

This question stem is one of those weird ones that asks you to focus on the Evidence. Typically, those are about coming up with an alternate explanation for a curious fact, or about pointing out a methodological flaw.

Here, because the evidence is statistics, we would want an answer showing us that the statistics are measuring the wrong thing or giving us an incomplete picture, I suppose.

14.

The relevance of the evidence cited by the government officials in support of their position would be most seriously undermined if it were true that

most species of plant and
Out of Scope: where most flourish
This answer is like saying, "I don't believe there's an opioid epidemic facing rural America, because most Americans live in urban areas." This answer has nothing to do with the author's evidence (global ozone levels).
1% picked this
decreases in the amount of
Strengthens, if anything
This answer would help the author support her view that there's nothing to worry about. Global ozone is constant. You may have just been looking at the polar ice cap ozone layer during its seasonal dip, but it's just a seasonal dip, not a permanent new low.
18% picked this
decreases in the amount of
No Impact
It wouldn't change the argument if people in the 1930's were also worried about decreased ozone, or if this is the first time it's ever happened. We're trying to assess whether the government's current statistics show that there's currently nothing to worry about.
4% picked this
Correct
quantities of atmospheric ozone shifted
Why this is right
This takes the classic Weakening form of showing how the author's Evidence is compatible with the opposite of her Conclusion. We'd use this answer to say, "Yes, global ozone is constant, but ... there's still reason to worry about UV pouring in through thinning ozone over the polar regions. When ozone thins out there, it travels to other parts of the atmosphere. So, yes, the total amount of ozone is constant, but it's gotten blobby. It's unnecessarily thick in some areas but dangerously thin in the polar regions; thin enough to let in UV that will harm marine life." I think this correct answer would have made just as much sense on a conventional Weaken question stem that asks us to weaken the argument. But it is showing that announcing "global ozone totals" is not relevant evidence, if we're actually having a conversation about a localized part of the ozone over the Antarctic. Turns out that the ozone layer is not uniform / homogenous, so global realities do not necessarily describe local realities.
Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.
65% picked this
even where the amount of
No Impact
Yes, we know that some UV always gets through, but we're worried that "so much harmful UV radiation" is reaching Earth where the ozone layer has decreased in Antarctica that it will rise to damaging levels. When you get a dental x-ray, if you declined the x-ray blanket they use to cover your heart by saying, "Oh, I get hit by x-rays whenever I go through security at the airport", the dentist might say, "True, but this is a stronger x-ray, and the effects of x-ray damage are cumulative, so you would be wise to minimize the amount of exposure you get to x-rays".
12% picked this

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