user19099: I couldn't find info on whether this question has been asked before, but here @fileunderwater says (for homework tag):

It is used a lot, it is clearly informative, and some people (myself included) use it to filter questions. It also categorizes questions, which is arguably what tags are for. The tag is also the second most used one at Chemistry-SE and Physics-SE

Recently, there has been a flood of homework questions on Biology.SE and many of them have been closed as off-topic too, but I've seen some homework questions with homework tag which are still open and have almost no research effort (or maybe I couldn't notice any effort shown).
So, my question is Does putting a homework tag in your question make the question less likely to be closed, even if it has no research effort?

user3340: No. Adding a homework tag makes no difference to the closure conditions. It is just a relevant tag that can help classify the question. 

user1590: Certainly some users are abusing the homework tag in attempt to get away with zero effort questions. We have to stamp this behaviour out. Adding the homework tag does not excuse a lack of research effort and we need to remember that as a community. 
Please continue to close questions as homework if they show insufficient research effort, regardless of whether it has been tagged as homework.
From what I can see, adding a homework tag is reducing the likelihood we will close a question, and it should not. Adding the tag does not change the closure conditions.

" Homework questions are off-topic on Biology unless you have shown your attempt at an answer. For more information see our homework policy."

The answer to your question in adding the homework tag should not make a question less likely to be closed, but currently it does seem to (to me) to reduce that likelihood.

19099: <p>I couldn't find info on whether this question has been asked before, but <a href="https://biology.meta.stackexchange.com/questions/3233/whats-better-closing-as-homework-or-adding-homework-tag">here</a> @fileunderwater says (for <code>homework</code> tag):</p>

<blockquote>
  <p>It is used a lot, it is clearly informative, and some people (myself included) use it to filter questions. It also categorizes questions, which is arguably what tags are for. The tag is also the second most used one at Chemistry-SE and Physics-SE</p>
</blockquote>

<p>Recently, there has been a flood of homework questions on Biology.SE and many of them have been closed as off-topic too, but I've seen some homework questions with <code>homework</code> tag which are still open and have almost no research effort (or maybe I couldn't notice any effort shown).</p>

<p>So, my question is <strong>Does putting a <code>homework</code> tag in your question make the question less likely to be closed, even if it has no research effort?</strong></p>
 3340: <p>No. Adding a homework tag makes no difference to the closure conditions. It is just a relevant tag that can help classify the question. </p>
 1590: <p>Certainly some users are abusing the homework tag in attempt to get away with zero effort questions. We have to stamp this behaviour out. Adding the homework tag does not excuse a lack of research effort and we need to remember that as a community. </p>

<p><strong>Please continue to close questions as homework if they show insufficient research effort, regardless of whether it has been tagged as homework.</strong></p>

<p>From what I can see, adding a homework tag <em>is</em> reducing the likelihood we will close a question, and it should not. Adding the tag does not change the closure conditions.</p>

<blockquote>
  <p>" Homework questions are off-topic on Biology unless you have shown your attempt at an answer. For more information see our homework policy."</p>
</blockquote>

<p>The answer to your question in adding the homework tag <em>should</em> not make a question less likely to be closed, but currently it does seem to (to me) to reduce that likelihood.</p>
