I am a finishing PhD Student in Neuroscience applying for the Medical School, and it has been some years since my undregraduate. I am thinking of whom to ask for the letters of recommendation, and unfortunately, I have nobody (professor, mentor, boss) from Humanities to ask for a letter from, while I have many people from the Science side. I heard medical schools want to see 1 letter from Humanities professor and the rest from science. Is this true, or can I have all my letters from the people from science, given my background?