Science

You have to select biology stream in class 11th and have to get a good knowledge of basic biology.

Hello Rahul,
It is difficult to answer since this depends on the university. There are so many in Australia. Your backlog is too much, I doubt if a top university like the University of Melbourne will happily accept. Keeping aside the backlogs, see that you meet the admission requirements, have the minimum academic percentage, required IELTS and so on. Apply accordingly. The entry requirements are naturally different from the universities so you have to visit the websites and start preparing accordingly.

No not important !

JNU entrance exams for this upcoming year already took place in December.

For M.Sc Zoology, DU & BHU are kind of best universities followed by JNU. You can also opt for integrated M.Sc, Ph.D from various institutes like TIFR, IISER, etc., by clearing various exams.