The logical chain from support to conclusion makes sense to me, but I have a quick question about navigating the conditional relationship indicators that help us get there in this question.

Stimmy says "all that would be needed to make money disappear would be a loss of universal belief in it." In my mind, this is equivalent to saying that a loss of universal belief in money is necessary, in fact the only necessary thing, for money's disappearance, making the relationship disappear -> loss of belief. But after some further thought, if loss of universal belief is the only thing needed to make money disappear, it makes sense that a loss of universal belief is sufficient to conclude that money has disappeared. How would you recommend we navigate tricky language like this? In my mind it could have gone either way.

@Stas1973 I agree. I only got there by process of elimination. Almost eliminated A at the jump because I thought building and refitting were considered in the stimmy when it talked about long-run costs.

I eliminated AC B because I thought that just because most dairy consumers consume less lactose than a liter of milk at each meal, they could still consume an equivalent or greater amount of lactose over the course of their three daily meals/daily intake that would make a liter of milk a comparable amount. Where'd I go wrong?

Is it because the experiment was only testing on lactose intake in a single sitting, making it comparable to a single sitting for a meal?

The correctness of AC E is not computing in my brain. Humans can't get WNV from each other, great. As J.Y. says, what's to say 100 North Americans travelled to Northern Africa in the 1990's, were all bitten by WNV-carrying mosquitos, and then "carried" the disease back to North America? They can't give it to any more humans, but they still surely "carried" the disease to North America? The disease is now in North America, brought in the immune systems of the afflicted humans. In what world does that not constitute "carrying"?

The only way this AC makes sense to me is if "carry" is meant more specifically as "spread" or "infect." West Nile virus was certainly not spread through North America by an infected person, that checks. But AC E seems to be operating with a very limited, specific definition of the word "carry," how are we ever to know that the test writers actually mean a more specific medical process of spreading or infection by the simple verb "carry"?

I was able to get this question right because no other AC was really a possibility, but I'm wondering about the role of the word "suitable" here in the stimulus versus the AC. AC D says that breeding territory suitability is determined by observing another breeding pair there, explaining why they choose to oust the breeding pair instead of going for vacant lakes. But the stimulus describes the vacant lakes as "perfectly suitable." So are we to assume that the suitability determination in the stimulus was made by humans or non-loons and that the loon determination of suitability, tied to presence of another breeding pair, is more trustworthy than that suggested in the stimulus, thus in a way overruling the suitability determination of the stimulus? I'm wondering how we balance similar terms that are mentioned in the stimulus and answer choices. In a harder question with more attractive alternative AC's, would the fact that vacant lakes have already been said to be suitable in the stimulus make the suitability determination made by the loons less attractive of an answer choice?

I wasn't sure about A because even if darker roasts have more caffeine, if darker roasts also contain NMP that mitigates the production of irritating acid, would the additional caffeine really matter if its harmful effects would be mitigated, if not prevented entirely?

@MarcusTsang Thanks for this explanation. Similar to Arjun my thought process was that since there is no evidence of humans acting selfishly more than unselfishly, they must act selfishly and unselfishly equally or they act unselfishly more often than selfishly. Now from your explanation I know that there is no evidence for either really in the claim. But my biggest takeaway from the negative comparisons lesson was the two correct interpretations that can come from a negative comparative relationship. But in this case a lack of evidence for X>Y doesn't necessarily imply evidence for X=Y or Y>X because there's no evidence for anything? I'm a bit confused about how to draw inferences from these sorts of questions, but I guess that's the point that no inferences can be drawn in either direction because there's no evidence provided?