I think what you're referring to is the premise to conclusion bridge, in which case, yes, you would be correct to think of it that way. When you're trying to find the P->C bridge for PSA or SA questions, the premises must trigger the rule (sufficient condition must be true to trigger the conditional) in order to arrive at the desired conclusion (the necessary condition).

Correct answers to Sufficient assumption questions will typically carry strong/powerful language! Don't let that deter you from selecting the answer choice. Similar to the approach with RRE and Weaken, Strengthen, and Evaluate. The question stem says "if assumed," so you're safe to assume whatever the answer choice tells you. The task then comes down to applying the facts in the stimulus to the "rule" in the answer choice, and checking if the conclusion would logically follow (i.e., the conclusion must be true if the answer choice was added to the stimulus).

I also struggled with this question and ended up picking B through POE -- A and E were referring to an irrelevant subset of bacteria, and C and D did not strengthen the argument.

What really sold me on B was "... but is in other respects similar to normal sewage": now that we have a comparable group of bacteria that did not live in heavy metal (HM) sewage, all other things being equal, we effectively have an experiment that tells us the bacteria found in HM sewage (stimulus) were resistant to antibiotics, whereas the bacteria the bacteria found in HM-free sewage (answer choice B) were resistant to neither HMs nor antibiotics. As a result, we can reasonably conclude that the causal relationship is strengthened, and that it isn't due to other possible chemicals or even antibiotics in the sewage, for example (there could be other alternative explanations for why the bacteria presented antibiotic resistance). To put it another way, the adequate design of this experiment that is created between the stimulus and answer choice B allow us to eliminate potential alternative hypotheses.

B does more than affirm the correlation between these two observations: it turns HM exposure into a "treatment," where the bacteria group in the stimulus is the treatment group and the bacteria group in answer choice B is the control group. Admittedly, this is a weird iteration of the "ideal experiment" subtype of weaken/strengthen/evaluate -- I didn't catch this at first because I expected the experiment to be more explicitly laid out in the stimulus. Hope this helps..!

#feedback 16:25 ish -- JY says that those who underwent surgery are just as or MORE likely to snore than those who haven't, but I believe he meant to say that those who underwent surgery as just as or LESS likely? answer choice (D) says "no more likely." Or am I misunderstanding the grammar here? I could just be going insane but I've been trying to grammar parse this for the past 15minutes...

The standard diagnostic LSAT is June 2007, which I believe is made available for free by the LSAC. You should be able to take that on 7Sage and get an idea of where you are starting from. Most people, I would say, try to keep PTs 80 and higher for serious practice, and use any older tests for drills, untimed practice, etc. I believe the June 2007 PT is somewhere in the 70s. Keep in mind that really old PTs do feel different from the modern LSAT, because there have been slight modifications in the formatting, types of questions asked, etc. I believe June 2007 was when the LSAC included a two-part reading passage in the RC section, for example. Hope this helps!