I am goin to be a re-app this year and thought that I might as well obtain new recs. I asked one of my previous profs for an app and he responded with "I will write you a great rec but are you sure you want me to write one because I only knew you for a semester." Do you guys think I should take the rec or not because he is hesitant? It's tough trying to get to know a science prof for more than a semester because of their busy schedule and in my case, I met this great prof during my last undergrad semester. What do you guys think? Suggestions?