A common misconception on the LSAT is that “principle questions” are a thing. In fact, the word “principle” appears in multiple question types which you should treat very differently. The most important thing to look for when you see the word “principle” is whether the principle points up or down. Some questions (PSAa or Rule Application questions) give us a principle in the stimulus and ask us to apply it down to the answer choices. These are akin to Most Strongly Supported questions, where we must be cautious of overstrong language and stick only to inferences supported by the stimulus.

This question (a PSAr or Find The Rule question) does the opposite: it presents a bunch of principles in the answer choices and asks us to apply them up to the stimulus in an effort to justify the argument. These are akin to Strengthen questions, where overstrong language is completely fine and we’re hoping to bridge any gaps in the argument we can find.

PSAr questions tend to follow routine patterns, and our approach can therefore be similarly routine. First, it’s critical to identify the argument’s conclusion and the premise(s) that seek to support it. In a shockingly high proportion of PSAr questions, the correct answer will take the form: Premise → Conclusion.

Like in normal strengthen questions, though, it’s also important to note any common flaws you see, or (especially) subtle jumps from one concept to another (e.g. from talking about athletes to talking about professional athletes). Correct answers that address weaknesses like these are common as well.

Right off the bat, the argument’s normative conclusion should make us suspect that our answer might bridge the is-ought gap. But it’s immediately followed up by a normative premise, so in this question the is-ought gap doesn’t apply – going from normative premises to a normative conclusion is fine.

Here’s the overall structure:

Premise 1: Discovered shouldn’t mean invented.
Premise 2: Exploiting genes for profit is selfish.
Conclusion: Patenting genes should be illegal.

There are tons of gaps between concepts here, and closing any of them would help the argument. For example, a correct answer could say…

Selfish stuff should be illegal
Patenting genes counts as exploiting genes
It should be illegal to patent stuff you haven’t invented.

Or, spoiler alert: if you merely discovered something, it should be illegal to patent it.

Note here that while there’s a world in which any of the above anticipations could be correct, in this question our correct answer follows the very common pattern of Premise → Conclusion.