Hey guys, just wondering if anyone knew if it was OK to use a research P.I. as one of our science faculty LOR's. My PI is an associate professor, but he is also faculty. I haven't taken any classes from him (I'm not sure if he even teaches undergrad classes anyways), but I have been working in his lab for a few months now and got a really good LOR from him. Could I use him as one of my two required science professor recs?