<p>Would submitting one be the difference between getting in and not?
I could get my AP Bio teacher to submit one she's written for an internship (She talked about how I took the class as a sophomore and how I pulled through)</p>
<p>In a theoretical sense, an additional LOR could perhaps be the difference. From a realistic perspective, it will not help and might even hurt your application - overworked adcoms already have too much to read.</p>
<p>Colleges ask for a specific number of LOR for a reason. Additional LOR should be sent only if they provide a perspective not available in the required LOR. Perhaps you work at a part-time job and your boss could write about how you show up for work at 4 am every day before school. Similarly, you could have your violin instructor write about your years of preparation paying off in a concert at Carnegie Hall.</p>
<p>My guess is that your AP Bio teacher would discuss qualities of yours that are similar to the two teachers that you have already submitted. I would not submit it.</p>