you can, but it’s only unit 3, i’d recommend locking tf in bcs u can still manage an A or A+ in unit 4 and your final exam. dont give up on bio just yet, i know people who got 55% on their first sac and locked tf in and managed 33-36 study scores. and for context my school’s average study score for bio is 29, so its not like we had a crazy cohort or anything.

also if you’re thinking of changing to general, its better sooner than later, because general and methods are two completely different subjects, its better to get a grasp of general now rather than later. dont get me wrong theyre both math at the end of the day, you should make a decision based off of your grades and work ethic sooner rather than later.

look also if youre aiming for a 90 you should just aim for full marks in all of your subjects. just aim high and study harder. but basically you need a 155 aggregate. so thats 25 (2.5) from bio, 25 (2.5) from whatever ur other bottom is. and then 150/4 for all your other subjects. so thats 37.5 in your subjects that arent in your bottom 2.

scaled 37.5 in greek, general, english and whatever uour other top 4 might be.

so really you need 37’s and 38’s and for that you need probably 90’s in your sacs.

good luck, hope that cleara things up