Good news: I got it right and fully understand how I arrived at a confident answer

Bad news: it took me 9 minutes to work through lmao

All cats are sufficiently mammals but not all mammals need to be cats

It is /enough/ (sufficient) for an animal to be a cat to be considered a mammal

It is /not enough/ for an mammal to automatically be considered a cat (it needs to be explicitely a cat to be considered a cat)

the trick is to seek out semantic logical equivalence - "not all are beneficial" = "some fail to be beneficial"

#feedback

I understand that B is confusing sufficient and necessary, which is fundamentally why it is wrong, but I also eliminated it because the rule dictated in the stimulus states "[the Florida panther] population must reach at least 250 in order to be self sustaining" while answer B states, "If the population of Florida panthers ever exceeds 250, it will be self-sustaining". What made me detect this answer as wrong (before actually considering the sufficient-necessary inversion), is the difference between reaching at least 250 to be self-sustaining and exceeding 250 to be self sustaining.

Let's imagine that, for Answer B, the sufficient and necessary weren't inverted and that Answer B instead read as follows: "If the population of Florida panthers ever becomes self-sustaining, its population has exceeded 250".

In Lawgic, such an inverted (corrected) Answer B would be:

SS --> 250+

Since the stimulus mentions that the population must only be at least 250, not necessarily exceed 250, doesn't the stimulus Lawgic actually require "greater or equal to 250", not "more than 250" as JY indicated above? I understand the stimulus Lawgic should actually be:

SS --> 250≥

If this is the case, Answer B is not only wrong because the sufficient and necessary are confused, but also because self sustenance would require even just 250 panthers, not necessarily an excess of or more than 250 panthers.

With this in mind, I would notate (a corrected sufficient-necessary) Answer B as follows if I wanted to check its validity:

(FP = Florida panthers)

SS --> FP^250≥

------------

SS --> FP^250+

Not valid.

Any feedback, confirmation, or explanation as to why this is wrong, would be very appreciated!

I just did three drills, increasing the difficulty each time and studying my errors in blind review and via the explanations afterwards, noting real lapses in judgement or things I need to keep in mind for future questions.

Doing this each round, I got three q's wrong on the first medium-difficulty mode, two wrong on the harder-difficulty mode, and zero wrong on the last, hardest-difficulty mode. I am just sharing this in case others beat themselves up when they get a question wrong, since I definitely do. These drills have been the first time in my studying where I am seeing myself actually developing technique and learning the strategy in a more linear and logical fashion, in turn actually arriving at results.

Be gentle with yourself! I haven't been and I needed this reminder that its just a process and a learning curve.