So I currently have 4 letters that can be used. One is a committee letter, one is from a dentist I shadowed, and two are from science professors. However, those two from science professors were also required to be sent at a specific deadline for my school's pre-health program. Is the committee letter based on my two letters I sent in? Would it suffice if I just sent in a committee letter and a letter from my dentist? Or should I send in all 4?