Even if ALL mammals that ARE deep divers have porous bones, that doesn't mean all mammals with porous bones are deep divers. If a mammal is a deep diver -> it has porous bones is not the same as If a mammal has porous bones -> it's a deep diver. Having porous bones would be a necessary, but not sufficient condition for being a deep diver. So, yes, it would be one "clue" needed to perhaps conclude that a mammal is a deep diver but it wouldn't be enough to conclude that like the stim did.

Answer choice (C) gives us a reason to believe that there are mammals out there with porous bones that are not deep divers -- and a strong one -- "most" mammals that are not deep divers also have porous bones. I believe it tell us that having porous bones is not sufficient to make a mammal a deep diver. Why? Because if it was sufficient, then no mammals would exist that have porous bones but are not deep divers. So really I don't think this answer choice would even have to say "most" to be correct; it's just more convincing that way.

Knowing that, the author's conclusion is weakened because it is assuming that having porous bones is enough to determine a mammal is a deep diver.

Answer Choice (D): Privatizing the national parks would benefit a much smaller number of consumers to a much smaller extent than did the privatization of the telecommunications industry.

Author's conclusion: The privatization of the national parks would probably benefit park visitors as well.

(D) word for word actually affirms the conclusion because it outright declares that privatization would benefit park visitors. If anything, it strengthens the argument by telling us for a fact that at least some (maybe not many, but some) park visitors would benefit. Remember, the author's conclusion was not that many visitors would benefit or that as many visitors would benefit in the park scenario as they did in the telecom scenario - just that some visitors would benefit. That could be 1 visitor or all of them.

I had the same issue but if the success of the new campaign is so big that it outweighs any potential cost of endanger the company's overall position, that still means what we want is a positive outcome for the company's overall position.

Answer choice (D) explicitly tells us the company's position would be negatively affected. If a manager wants a product to do well, it's reasonable to assume it's because they want the company to do well overall.

FWIW, I think it's important to highlight that answer choice (B) refers to "some" halophytes. We don't know if that's relevant to the argument as it may, or may not be, the same subset of halophytes spoken about in the stimulus - so you can probably eliminate it just off that.

(D) doesn't need to specify timeframe. It could if it wanted to be more narrow, but the rule it gave us is more broad than we needed, which is fine in this case.

If it's true under all circumstances that the only way to determine the existence of sentient beings on planets outside our solar system is either to (1) send a spacecraft or (2) to communicate with them - then it's true that is the case for the near-future as well. I.e., think of the "near future" as being a subset and "infinity" or "all time" being the superset.

The example you gave of a future technology is not relevant. We assume the answer choice (D) to be true and if it's true then nothing in the future will change the fact that those are the only 2 ways to identify the existence of sentient beings on planets outside our solar system. Does that help?

By definition a government agency is part of the public sector, so something can't be both a gov't agency + a private, for-profit company. Thus, "water should be supplied by a government agency" = water should be supplied by something that is not a private, for-profit company.

That's how we get to the conclusion that it shouldn't be supplied by a private, for-profit company.

Analogous to toppled trash bin: On Friday afternoon Emily was spending time with a friend of hers who wasn't feeling well. Two days later, she came down with a cold. Surely, Emily's friend must have been the cause of the cold.

Analogous to Disney: To get a premium credit card one must either have a credit score greater than 800 or have at least $10,000 in their chequing account. Adam has a premium credit card and his credit score is 750. Therefore, Adam must have at least $10,000 in his chequing account.