Does it matter with the conjunctions or conjunctive adverbs? I think in the example it does not matter since like "after all" seems like a concluding conjunctive adverbs. However, in other cases, would conjunctive adverbs be a good hint to identify conclusions or serve as something that tricks people taking the test?

I know LSAT test designers can make tricky questions like this. Sometimes it requires me to take time to process it. Is there any methods to be more sensitive about it by the first time reading questions? How to practice this kind of sensitivity or awareness?

This question is similar to PT54 S4 Q11 I did in the same drill. For both questions, I could not figure out whether the conclusion was sentence 1 or sentence 2 (the "thus" sentence was pretty clear for me that it was part of the premise).

From both questions' explanation videos, I think that sentence 2 was the conclusion was because it introduced a hypothesis (or a completely new idea), which made sentence 1 only a fact (or context) so that sentence 2 was not 100% supporting sentence 1. Instead, it provided a "possible" explanation for sentence 1, which should be the author's main point.

In other words, the logical link (metabolic quirk of the brain -> sentence 1) is only a hypothesis. It is not an actual logical link, so S2 does not actually support sentence 1. The entire premises after the conclusion were supporting the hypothesized logical link (or the main point).

Both questions' hypothesis sentences contained the word "probably," which could be seen as a possible indicator that they were hypotheses.