Hey thanks for your replies, seriously! :D
Frankly speaking, I've been too occupied with seeking help for
my 2 other sciences and amaths. I was failing amaths all the way or
having borderline passes last year and it's only this year that I'm
starting to get my A1. As for my physics, I started out very weak
last year as well and I've been trying to stabalise my A1 as well,
as for chemistry same story.
For the past 2 years, my Biology has always been B3 (which I felt
is okay, since I think I had to stabalise my confirmed A's first)
and Biology was sort of a back-up in case anything unexpected
happens during O'levels and it will end up becoming one of my r5,
and then finally for prelims I got a C5 (yes, I studied), which
kind of told me it's time I do something about Biology, and that's
why I'm here asking for advices on how to study Biology more
effectively because maybe what I'm doing is wrong.
It may seem like 'I deserve it' but I really do put in effort
for any Biology exams. I'm not wanting too much for O'levels, I
know I can't get distinctions for it, but I just don't want a C
again moreover for the last time since I'm pretty sure I'm not cut
out for Biology.
Yes, why didn't I drop Biology? My teacher told me time and time
again not to, because she keeps believing that I can do it. And I
enjoy Physics and Chemistry, so I didn't drop them to make way for
Biology.
Sounds like excuses for myself though, I know. Thanks a lot once
again anyways! :) I guess I'll just have to do what I can for now
and do my best, and hope you guys would help me if I post any
questions which, I will provide my answers in the first place!
:)
You're welcome 
As for 'A' levels (if you choose JC route instead of Poly), then
you'll have to re-decide if you want to take triple science or
double science. Probably you'll go for Phy and Chem. But
personally, Chem and Bio are a lot more interesting, any at level
('O', 'A', University).