I'm a rising senior in college and I'm looking into grad programs in biology. For the Letter of Recommendation requirement I have found that usually 3 are required.
Currently I can only think of 2 mentors who are in the field of study I would like to go into who can write strong letters. Is it bad if the third came from a professor in a completely different field, or as I like to think of as the humanities research that interprets the science research I'm interested in? Thank you!
Or should I ask one of the post-docs in the lab I work with (in addition to the PI of the lab) since they are working in the relevant field?