I know that Jefferson requires one letter each from a physic, chemistry, and biology professor. Does anyone know if Jefferson make exception if you cannot obtain these letters? I have six letters but missing two from chemistry and physic departments. I've emailed them and asked if they make exception because I feel I have more than enough letter for them to read and get a feel of who I am with respect to my professor/boss/PI. But I have yet to hear back from them regarding my question. I emailed them about a month back.