I am 4 months away from my A-level exams and I have just received a U in my last biology mock. This came as a shock to me because I spent around 2 months revising for this exam, where in the 3 weeks before the exam I would revise 3 hours a day on average (for biology alone). I don't understand what I did wrong. I went over all the content and did exam practice. My parents have told me that 3 hours a dah is not enough and that I should increase how much I revise significantly. How many hours should I revise a day for OCR biology and what are some revision techniques which may aid me? I would apprectiagte any pieces of advice.