IISER Entrance Exam

That is a good score from SC category but you need to go through last 2 year's cutoffs.

No, you can't fit into IISER.

Kindly refer to the link mentioned below:
https://www.shiksha.com/science/exams/iiser-entrance-exam

You cannot get the IISER question papers from anywhere. The reason is they do not let you to take the question papers outside. And the main reason for this is that they do not want the private coaching centers to get in this field (I specifically asked the exam coordinator about this. )
All you can have is the two mock papers from the IISER admission website. If you really want previous years papers, then you must practice the prev. Papers from NEST of NISER. It is a very similar institute in Bhubaneswar and even better than most IISERs or at par with it.

Please check for your eligibility to appear for the IISER entrance test from the criteria mentioned at the link provided below:
https://www.shiksha.com/science/exams/iiser-entrance-exam.

Your total percentage will be considered.

Hi,
NCERT Biology textbooks. It is the best for IISER Aptitude test. Try to complete class 12 standard textbooks, as much as you can. Most of test is from class 12.

Hi,Yes, biology is a compulsory subject for IISER aptitude test. As most of the questions in aptitude exam are basic ones 10+1 and 10+2 biology NCERT books are more than enough.