biology is mindnumbingly easy for everyone i know who is doing it and myself. if memorising chunks of information is a talent of yours then you are going to do excellent in it. a lot of it is common sense. you should already be able to give reasons why australia is part of gondwana and be able to write lots of crap about ecosystems.
but i hope you are prepared to give up your social life for maths ext. 1. i started with it and lasted a term. i finished 9th in my year in year 10 but i don't do homework. which is why bio is good and maths is bad for me.
english advanced moves in sudden bursts and then freezes. one day you will just watch a movie. bludge. then maybe three weeks later you can be asked to write a thousand words over a week about the representation of gender or the state of the society portrayed. keep on top of the formatives and you will have nothing to panic about. most of the time it's pretty frozen.
studies of religion is a subject i could go on forever about. so easy. especially for students in the catholic system since kinder. it's basically religion for dummies 101. you just have to learn a few basic beliefs, a few important people's names, a few symbols ect. nothing complicated.
i approve of your subjects (not that that really means anything) and hope i havn't scared you off them or put you to sleep with this essay. ext. english rubs off lol