The listed prerequisite is just Grade 12 Bio but I do know that they always reserve seats for science students and you may run into issues on Mosaic when enrolling where it might give you a message saying "seats are not reserved for you" or something like that.
If that's the case, there's usually a week or so after classes start where you can switch around your classes and in that time period people usually drop or switch out so you can switch in then if you can't enrol during your enrolment appointment. If around that point it's still not letting you switch in then you should contact the science faculty at
[email protected]. But obviously, make sure you're checking this stuff out days before the drop/switch deadline.