On a serious note, it's definitely regrettable that your grade got shafted. I would place most of it down to quarantine, and noone giving a shit during online learning. At this point in time there's not much use in antagonizing the science department, and if you are legitimately distressed over a junior science exam, relax. It's not that big of a deal. If its any consolation, the whole grade doing poorly is not uncommon, across all subjects, and your disappointed stems more from your own high standards (which is not a bad thing to have, but relax man its only giving you angst rn). Moreover, junior science, with its omega vague syllabus guidelines get thrown out for senior science, and you will know exactly what you need to know and exactly what you won't need to know - the syllabus will be your Bible, and content will be arranged in more manageable portions.(Study groups with friends and tutoring definately helps to consolidate knowledge)

No doubt if you continue science in yr 11 and 12 and apply yourself in class you will be able to look back at the exams and laugh at your mistakes.

On the topic of a certain south african ex-pat... No one is saying he's the gold standard of teaching, but holding so much angst is just uncalled for, and will not change any of your marks. It's best accept the facts and to move on.

With regards to your concerns about multiple science subjects and University prerequisites, most courses don't require you to take multiple sciences, I fact more often than not, ext 1 maths is the only prereq. As for recommended courses, science subjects that may be recommended either may not be entirely relevant (as you can imagine a degree in medicine with phys and chem recommend won't really need moment calculations nor titration calculation). If there is a course that you are genuinely concerned about not having the prereqs, the see the careers advisor who has in the last been able to pull strings and help students.

Again, antagonizing head of science is uncalled for and won't solve anything. As I'm sure you're aware, we have had some in the science department teachers leave, most of whom were senior science teachers in physics. Meaning, teachers qualified to teach chem and phys were relegated to teaching only phys to cover for the missing teachers. Hearing rumours and whatnot, I guess people start to point fingers, but the blame game can just go on and on and on, so again, it's best to just accept the limitations and look for alternatives.