QUESTIONS ABOUT: SUBJECTS ASIDE FROM COURSE

helloo, currently in yr12 and was looking at potential courses! i was looking at dentistry and I think to my understanding we need to do an undergrad degree and if we score well enough in the gamsat + high gpa I can potentially get in? which brought me to the prereq required being:

• Anatomy: ANAT20006 Principles of Human Structure
• Biochemistry: BCMB20002 Biochemistry and Molecular Biology
• Physiology: PHYS20008 Human Physiology

I understand that we can choose degrees which cover this like oral health, biomed & science, but I wanted to maybe keep my options a bit more open by doing something like commerce (still deciding)... and so if I have to take these prereqs, can I just take additional classes that are outside my degree? like is that even possible + how would the fees work

if anyone knows plz do help, thank you in advance ^^