Logical reasoning PrepTest 140 · Section 2 · Question 12

Incorrect. The opposing point conditions its claims on the population growth trends continuing as is, and the author's argument states that something won't happen regardless of current trends, so the reliability of predictions are out of scope.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Humans use only a small fraction of available fresh water, so we're not headed for water shortages even if the population keeps growing.

Answer Anticipation:
We rephrased the conclusion here a little bit to reflect what the author is actually stating. In concluding that claims are "mistaken," the author commits herself to believing the opposite. Those claims are that we're headed for water shortages if the population keeps going up, so the author's conclusion is that we're not headed for such shortages even with an increase in the population.

Why does the author believe that we won't have water shortages? Because the supply of fresh water is way more than enough to meet current demand, so even if demand goes up somewhat, there should still be enough. Is there being enough of a supply to meet demand enough to establish that there won't be shortages?

Absolutely not. Think about food—there's more than enough for everyone to eat, and yet there are still plenty of people who go hungry because they don't have access to that food. The same could be true for water—it's possible that, overall, there's enough fresh water for everyone, but it's not accessible for many, and so increasing the population could drive this unequal access into water shortages. Any answer that gets at this idea of access to water being different from overall supply will weaken the argument.

Answer Explanation:
This answer addresses one aspect of access—distribution of the fresh water. If the vast majority of fresh water is available in certain countries, and others lack such access, then there could be shortages driven by population increases in these areas even if there's sufficient supply elsewhere to meet needs. This answer weakens the argument by drawing a divide between supply and meeting demand.

Key Takeaway:
If you're having trouble spotting a flaw, sometimes it can be useful to try to find an analogy for the argument that you understand. Here, we used the prevalence of food but the shortages faced by certain individuals to understand the flaw in an argument relying on there being enough water to meet demand not being sufficient to conclude there can't be shortages. If you can think of a similar situation on the spot, don't shy away from it!

Incorrect. The author relies on the much more than adequate supply of water to address claims of shortages, not the implementation of conservation methods, so this answer doesn't undermine her argument.

Incorrect. The argument is about whether there will be shortages in the "near future," so what will "eventually" happen is out of scope. Note that water is one resource, so this answer can't be eliminated because it discusses all available resources. What is true of all resources would be true of water, and thus an answer including that could be relevant to the argument.

Incorrect. Agriculture and industry are both human uses for fresh water, so these two uses are already taken into account when the author states that current use is much lower than available supply. This answer is trying to get you to think that these uses weren't considered by the author and thus might question the supply of drinking water, but the author spoke broadly enough to include these considerations.