I am a 3rd-4th year student planning to try and get into graduate school in my field of study. But I got some terrible marks in my first year in courses relating to my program (science and math courses), and in a non-related course. Since some universities specifically require an undergraduate 3.0 GPA to get into their graduate program, I was wondering if I should retake a few of these courses in my last year. In my university, marks from repeated courses will replace the original marks (but the original ones will still show up on my transcript). I am wondering if this would be a good idea, considering that my later year courses tend to build on my first year classes. Thanks.