retake courses vs taking higher level elective

[gator11]

I am a first year applicant and received two interviews but was waitlisted at both schools. I am still waiting on decisions from a few schools but need to start thinking of how i'm going to improve my application. I believe i have a pretty strong application except for one or two courses, core biology 1 and biochemistry. Didn't do so well in those two classes, so i'm deciding between retaking them or taking some other higher level courses. Any advice would be appreciated. 

[Hawkeyes]

I would take upper level courses rather than retaking courses, just make sure you do well in those upper level courses. What grade did you receive in the classes you want to retake? As long as you meet the grade requirement for specific courses (usually a C) for the schools that interest you, I wouldn't retake them.

[sobriquet]

I agree with Hawkeyes, I would take more upper level bio classes instead of retaking any classes unless the grade will give you an automatic rejection.  If you just retake a class, how does adcom know you've actually improved your studying skills and learned from your past "mistake" of the bad grade?  They could assume you just needed double the time in order to master the one classes material.  If you take an upper level class, and do well, then you can easily explain away a bad previous grade and prove that is not your norm.