<p>@specific, you're mistaken. I specifically (lol) mailed common app asking them that, and they said that you cannot ask another teacher to do it. this is exactly what the mail said:</p>
<p>"Unfortunately, only a counselor can fill out the counselor recommendation. The requirement for this recommendation is more about getting a feel for the academic environment of the school more than just a personal recommendation. The counselor's letter is intended to give admission committees a snapshot of your academic performance in reference to your peers and the opportunity available at your school.
You are able to add teacher recommendations to your application, and some schools even have a minimum requirment for teacher recommendations. Contact your school(s) of interest directly if you have any questions about recommendation requirements.
Again, thank you for contacting us; please do so again if you need additional assistance."</p>