First of all you need to specify the board in which you are studying in 12th class to get the model paper.on our platform there are various boards papers sample pdf available which is downloadable and can be use offline.

You are from chattisgarh so i am assuming that you might need CBSE, IGCSE or chattisgarh board sample paper.

All the model paper of biology subject is provided below which is helpful for your exam

https://school.careers360.com/boards/cbse/cbse-class-12-biology-sample-papers

https://school.careers360.com/boards/cgbse/cgbse-12th-question-papers

https://school.careers360.com/articles/class-12-sample-papers

If not useful please rewrite us we are here to help you in building your career.