I recently answered a one-line question. This question appears to have (very modestly) polarized the Bio.SE community: it has been up- and down-voted once each (not counting my upvote just now). My answer has been upvoted five times and downvoted twice as of now.
Position one
A comment by @David I think summarizes why some people are opposed to both my answer and the question- the motivation seems to be that people shouldn't be asking certain kinds of questions, or that some questions don't merit more than a brisk comment-as-answer, based on criteria like whether the asker has looked at the tutorial. My interpretation of this view: there is an algorithm that we use to exclude bad questions, regardless of considerations about question content. (I'll leave aside for the moment what that algorithm is or should be.)
Position Two
On the other hand, I think that the question is a good example something that is obvious to people who know a bit of biology and non-obvious to people who don't. From my perspective, it is therefore a high-value question, even though it doesn't necessarily meet other "good question" criteria like having sources or whatever, and the user is obviously new to SE.
Homework
The user did give it a "homework" tag, which is IMO better than a lot of such questions.
Notably, the question is not "answer my problem set for me", but "here is a thing my teacher said that doesn't seem to be supported, why do they say this?"
The former is obviously not a good question, the latter I would argue can be a good question. (One potentially relevant meta question w/r/t this is here.)
Actual questions
1) Are there substantive arguments one way or the other that I'm not summarizing here?
2) Are there any policies for questions where there's this kind of evident disagreement in the community regarding whether a question (or answer) is worthwhile?