biology is fine- as long as you can remember lots of long words XD it is really the only difference i found between gcse and a level
chem does get quite hard, and you have to make sure you understand as you go along and don't wait until just before the exam
maths- c1 is easier than additional gcse maths the rest are fine, basically just more maths (if you do M1, its kinda hard cause its basically physics)
im not sure about business studies