This is an RRE question.
The stimulus tells us that according to a new study, after a heavy rainfall, pollution levels in Crystal Bay reach their highest levels. We also learn that rainwater is almost totally pure. Together these constitute the phenomenon we are trying to explain. The stimulus also tries to generate a feeling of surprise or puzzlement by telling us what we should expect. That is, we should expect the pure rainwater to dilute the polluted seawater.
As with all RRE questions, whether or not we feel like the phenomenon is puzzling largely depends on what assumptions we were making. If we assume that the stimulus paints the whole picture, in other words, the phenomenon is merely as simple as that which the stimulus describes, then we might think this is surprising. On the other hand, if you are a subject matter expert, say someone who studies urban pollution, you probably already know that there are other factors at play. You probably already know the explanation for the phenomenon.
We don't need to be subject matter experts to get RRE questions right. We just need to keep an open mind about possible explanations.
Correct Answer Choice (B) says most of the rainwater that eventually reaches Crystal Bay falls on pesticide-treated fields before being carried into the bay. This is a specific version of what I described generally above. The story is indeed more complicated. While it's true that some rain falls directly into the bay and would have the effect of diluting the pollution in the bay, as it turns out, most rain doesn't fall directly into the bay. Rather, it falls onto land and then runs off into the bay, picking up and carrying whatever it is that it comes into contact with. This answer choice specifically tells us that it picks up and carries pesticides into the bay. We only need to assume that pesticides are a type of pollution.
Answer Choice (A) says compared to the total amount of polluted seawater in Crystal Bay, the amount of rainwater that falls into it is negligible. This answer choice might have worked had the phenomenon been different. If the phenomenon merely said that after a heavy rainfall, pollution levels remain unchanged in Crystal Bay, then perhaps this answer provides an explanation. Yes, it's true that rainwater is pure, which would dilute polluted seawater. But in order for the dilution to be measurable, there needs to be some minimum threshold amount of rainwater. For example, if you simply pour a bucket of rainwater into the bay, nobody would expect the pollution to be diluted because a bucket of rainwater is a negligible amount. That's what this answer choice provides. The explanation is that there just simply isn't enough rainwater. Fair enough, but the phenomenon above that we are trying to explain isn't that pollution remains unchanged after rainfall. Rather, it's that pollution reaches its highest levels after heavy rainfall. This answer does not explain that at all.
Answer Choice (C) says most rainwater carried by clouds consists of water that's evaporated from oceans around the world. This is irrelevant. C tells us the origins of rainwater. It treats rainwater as an effect and reveals to us rainwater's causes. We simply don't care about that. We already know rainwater is pure, and that sets up the expectation of diluting pollution in Crystal Bay. We’re simply trying to explain why that expectation was upset.
Answer Choice (D) says the single leading cause of pollution in Crystal Bay is beachgoers leaving behind trash which blows into the bay. In order for this answer to explain the phenomenon, we have to assume that heavy rainfall somehow causes more trash either to be left behind or to be blown into the bay. We might be tempted to say that rainfall tends to be accompanied by strong winds which would blow more trash and debris into the bay. Fair enough, but it still remains to be explained why the rainfall itself, which is mostly pure water, doesn't counteract the extra pollution from the trash by diluting the existing pollution in the bay. Contrast this answer with Answer Choice (B). There, we have no such lingering question. We are told there that most rainwater that reaches the bay carries pollution, which means that it's only a minority of rainwater that reaches the bay in its pure form.
Answer Choice (E) says other nearby ocean areas experience a pattern of pollutant increase and decrease that is extremely similar to that of Crystal Bay. This is a cookie-cutter wrong answer for RRE questions. This answer reveals a phenomenon consistent with the phenomenon in the stimulus and is also in need of an explanation just like the phenomenon in the stimulus. So rather than solving the problem, this answer only adds to the problem.
This is a Weaken question.
The stimulus starts by telling us that domesticated animals were created by the breeding of only the sufficiently tame wild animals. In other words, it's just a subset of the wild animals that were amenable to breeding for domestication. As an example, the argument uses dogs and wolves. It says that after a number of generations of breeding only the wolves that are sufficiently tame, we create dogs. That’s it for the premises. They’ve established how domestication occurs and provided an example of domesticating wolves to create dogs.
Now we get the conclusion. It says all animals can in principle be bred for domesticity. This conclusion is very weakly supported. The logic of this argument is that of generalization, which is a special kind of argument by analogy. The reasoning assumes that wolves are representative of all wild animals in terms of their potential tameness. More broadly, the argument assumes that just because some animals can be domesticated, all animals can be domesticated. Whether or not this is a reasonable assumption simply depends on the state of the world. If it's true that all animals contain some members that are sufficiently tame, like wolves, then this is a fine assumption. Otherwise, it's not.
Correct Answer Choice (C) reveals that the world is not one in which all animals contain some members that are sufficiently tame. It says that in some animal species, no members ever displayed tameness. That contradicts the core assumption of the argument and therefore weakens the argument.
Answer Choice (A) says domesticated animals cannot be turned into wild species by breeding only those animals that display some wild characteristics. This answer is talking about changing animals in the other direction, from domesticated to wild. It tells us that we can't select for the wildest dogs and breed them with each other and expect to get wolves as a result. That's good to know, I guess, but it has nothing to do with the argument.
Answer Choice (B) says in some animal species, wild members mate more frequently than tame members. So, for example, wolves that are wilder mate more frequently than wolves that are tamer. That is irrelevant to the argument, because domestication involves humans breeding the tame members of wolves. As long as those wolves breed at all, we’re good. We don't care whether they breed more or less than wilder members of their species.
Answer Choice (D) says in some animal species, tame members are less fertile than wild members. Just like (B), we don't care about the comparative fertility of tame to wild. As long as tame members are fertile at all, domestication can occur.
Answer Choice (E) says in some domesticated animal species, some members are much more tame than other members. This is obvious because you wouldn't expect dogs or cats, for example, to be all equally tame. Of course some dogs are going to be more tame than others, and of course some cats are going to be more wild than others. Tameness is on a spectrum. It's not a binary characteristic. But so what? The argument never assumed that members of a domesticated species were all equally tame.
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.