I assume you are doing AQA? Even if you are not, the papers for the CA are literally the same every year/session with the exception of a few questions. I got 50/50 on mine, all i did was print out all the previous CA papers + their mark schemes and forged a perfect answer for the questions that come up in every paper. The mark schemes vary each year, make sure to add in excess detail, e.g if you say that the higher the light intensity, the larger the pea pod, you have to say where you sourced your information from e.g GCSE bitesize