Surprisingly, a new study has revealed that shortly after a heavy rainfall, pollution levels in Crystal Bay reach their highest levels. This occurs despite the fact that rainwater is almost totally pure and one would therefore expect that it would dilute the polluted seawater.

"Surprising" Phenomenon
Why are pollution levels in Crystal Bay highest shortly after a heavy rainfall, even though rainwater doesn’t contain pollution, so we would expect rainwater to dilute the polluted seawater?

Objective
The correct answer should tell us something about heavy rainfall that might lead to an overall increase in pollution, even if the water in rainwater doesn’t contain pollution.

A
Compared to the total amount of polluted seawater, the amount of rainwater that falls into Crystal Bay is negligible.
This would lead us to expect rainfall to leave pollution levels unchanged. But we’re trying to explain why there’s an increase in pollution levels after rainfall.
B
Most of the rainwater that eventually reaches Crystal Bay falls on pesticide-treated fields before being carried into the bay.
This suggests that, although the rainwater itself doesn’t contain pollution, it can carry or otherwise bring pollution (pesticides) into the bay. This can help explain why pollution levels increase shortly after heavy rainfall.
C
Most rainwater carried by clouds consists of water that has evaporated from oceans around the world.
We have no reason to think rainwater from evaporation is particularly pollution-heavy compared to other kinds of rainwater. And, we know that rainwater is “almost totally pure.” So, we’d still expect rainfall not to increase pollution levels.
D
The single leading cause of pollution in Crystal Bay is beachgoers’ leaving behind their trash and debris, which then blows into the bay.
There may be other, more significant sources of pollution, such as beachgoers’ trash. But we don’t have any reason to think beachgoing increases or the amount of trash left increases after heavy rainfall. So, we still wouldn’t expect pollution levels to be highest after rain.
E
Other nearby ocean areas experience a pattern of pollutant increase and decrease that is extremely similar to that of Crystal Bay.
Even if other areas experience higher pollution levels after rainfall, that doesn’t explain why this pattern occurs in Crystal Bay. We’re still left without any reason to think the pollution levels would increase after heavy rain.

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Domesticated animals, such as dogs, have come into existence by the breeding of only the individuals of a wild species that are sufficiently tame. For example, if when breeding wolves one breeds only those that display tameness when young, then after a number of generations the offspring will be a species of dog. Therefore, all animals can, in principle, be bred for domesticity.

Summarize Argument: Phenomenon-Hypothesis
The author argues that in theory, all animals can be bred to be domesticated. This is based on the observation of wolves being selectively bred for their tameness. After several generations, wolves were tamed into dogs.

Notable Assumptions
The author assumes that the same conditions that can cause wolves to be domesticated into dogs are applicable to *all* other animals. This assumes that there are no biological/behavior limitations that prevent certain species from becoming domesticated.

A
Domesticated animals cannot be turned into wild species by breeding only those animals that display some wild characteristics.
The argument is not concerned with turning domesticated animals into wild animals. But wild animals into domesticated ones.
B
In some animal species, wild members mate more frequently than tame members.
While this could make selective breeding more challenging, it does not imply that it is “impossible” to domesticate all kinds of animals.
C
In some animal species, no members ever display tameness.
This directly challenges a key assumption: that all animals have the capacity to be tamed and bred for domesticity. This completely undermines the reasoning and weakens the argument.
D
In some animal species, tame members are less fertile than wild members.
Although this could make the process of selective breeding more challenging, it does not undermine the argument’s reasoning.
E
In some domesticated animal species, some members are much more tame than other members.
This is pretty much implied in the stimulus. It does not impact the claim that all animals can be bred for domesticity.

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Educator: Few problems faced in daily life can be solved most effectively, if at all, by applying knowledge from any single academic discipline in isolation. Thus, schools should not require students to take courses in individual academic disciplines but should instead require them to take interdisciplinary courses.

Summarize Argument
The educator concludes that schools should require students to take interdisciplinary courses, rather than courses in individual academic disciplines. He supports this by saying that few problems faced in daily life can be effectively solved by applying knowledge from any single academic discipline alone.

Notable Assumptions
The educator assumes that students can’t combine knowledge from different disciplines unless they learn to do so in an interdisciplinary course. In other words, he assumes that schools have to teach interdisciplinary courses in order for students to combine knowledge across disciplines. He also assumes that one of the goals of schools should be to teach students to effectively solve problems faced in daily life.

A
Problems faced in daily life usually can be solved effectively using only common sense.
This weakens the educator’s argument because, if students can effectively solve problems faced in daily life using only common sense, why does it matter whether schools teach interdisciplinary courses? Students can solve these problems either way.
B
Most teachers are able to teach courses in a single academic discipline more effectively than they can teach interdisciplinary courses.
This weakens the argument because it provides a consequence of switching to an interdisciplinary teaching model. If teachers are more effective in teaching single subjects, the quality of education may decline if the educator's suggestion is followed.
C
Students who take only courses in individual academic disciplines are rarely able to combine knowledge from those disciplines.
This strengthens the argument by addressing the assumption that students can’t combine knowledge from different disciplines unless they learn to do so in an interdisciplinary course. If that assumption is true, interdisciplinary teaching becomes much more necessary.
D
Most students who are required to take courses that cover only single disciplines can effectively solve many problems faced in daily life.
Irrelevant— the premise tells us that “few” problems can be solved using knowledge from any single academic discipline. It follows that some problems can be effectively solved this way, so (D) doesn’t affect the argument either way.
E
Most interdisciplinary courses are not designed specifically to teach students how to solve problems faced in daily life.
Irrelevant— just because courses aren't designed to teach students how to solve problems faced in daily life doesn’t mean that they won’t teach students to solve these problems.

This is a Strengthen question.

The educator's argument contains only one premise and one conclusion. The premise says that few problems faced in daily life can be solved most effectively, if at all, by applying knowledge from any single academic discipline in isolation. That means most problems faced in daily life cannot be most effectively solved by… [rest of sentence]. From that she concludes schools should not require students to take courses in individual academic disciplines but should instead require them to take interdisciplinary courses.

The argument contains a number of assumptions. One is the move from a descriptive premise to a prescriptive conclusion. The premise states what is the case. It is the case that most problems cannot be solved… The conclusion moves to a claim about what schools should do in response. That assumes that schools should try to help students solve the problems that they face in daily life.

Another assumption is that schools have to teach students interdisciplinary courses in order for students to combine knowledge from different disciplines. Is that true? If the schools don't teach an interdisciplinary course on, say, ethics and economics and instead teach those courses separately, does that mean the students can't combine knowledge from the two? That's not clear. But the argument assumes they can’t and concludes that it’s up to the schools to teach interdisciplinary courses.

Correct Answer Choice (C) recognizes this assumption and declares it to be so. It says that students who take only courses in individual disciplines are rarely able to combine knowledge from those disciplines. If that's the case, then the need for schools to teach interdisciplinary courses is much stronger.

Answer Choice (A) cuts against the first assumption we identified. It says that problems faced in daily life usually can be solved effectively using only common sense. If this is true, then who cares about whether schools teach disciplines in an isolated or interdisciplinary manner? If this is true, then the fact that applying knowledge from a single discipline in isolation usually does not amount to a solution doesn't seem like a problem at all, because students can just use their common sense.

Answer Choice (B) says most teachers are able to teach courses in a single academic discipline more effectively than they can teach interdisciplinary courses. This means that if the policy in the conclusion is implemented, then the quality of instruction will suffer as a result. Most teachers will become less effective than when they were in the past teaching single disciplines. This consideration certainly weighs against implementing the policy and the conclusion. So it doesn't strengthen the argument.

Answer Choice (D) says most students who are required to take courses that cover only single disciplines can effectively solve many problems facing daily life. This is not necessarily telling us anything new. The premise already made room for the information here. The premise said that few problems can be solved by applying knowledge from a single discipline in isolation. That already acknowledged the possibility that some problems can.

Answer Choice (E) says most interdisciplinary courses are not designed specifically to teach students how to solve problems faced in daily life. It's not clear if a course not being specifically designed to do a thing means that the course won't end up achieving that result anyway. But even if we assume that's true, meaning that because the courses are not designed specifically to teach students how to resolve problems in daily life, the courses therefore don't end up teaching students how to solve problems in daily life, then that's just the weakness of the policy in the conclusion. That doesn't strengthen the argument.


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Note: This is video #2 in a two-part explanation using the split approach for comparative passages. In the previous video, J.Y. already tackled whatever questions he could based solely on a readthrough of Passage A. In this video, he picks up with Passage B and then cleans up the remaining questions. So, if you don't see a full explanation for a given question in this video, it's because J.Y. tackled that question in the previous video. (Press shift + ← to head to the previous video.)

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