damn bio doesn't scale great in the first place but damn the scaling of the subjects you do is ass, maybe don't drop bio and drop one of the subjects with proper horrible scaling.
it is impossible to predict your bio raw mark besides multis since the marking criteria will just become stricter and stricter until they have a suitable distribution which is quite unpredictable for us so you cannot assume you got 100% on all the questions you did not definitely lose marks on...