coolbeans as wheat alr mentioned above, no u don’t need bio 1/2 to do 3/4, cuz majority of the 1/2 content is irrelevant, meaning it wont get tested on the final vcaa exam, but u can’t do an accelerated 3/4 subject in year 10, unless like your already doing a 1/2 this year and doing 3/4 someplace outside of school, but rarely only one or two kids do so like those who do a language or something. My friend did Chinese 3/4last year in yr 10.
