Personally I think physics would be better as it compliments both maths and chemistry well (and it is amazing. I know I am a geek). However, if you enjoy biology more and are good at memorising lots of stuff (as you must be if you are taking french) then you will be more inclined to revise it and will therefore do better. I am also in Year 11 and I am thinking of taking maths, further maths, chemistry and physics. How are you doing in those two subjects at the minute??? Is one stronger than the other??? xx