Hi

You can get and download previous years question papers and sample papers of NIOS for class 12th Biology and other subjects by visiting your page the link for the same as given below

https://school.careers360.com/articles/nios-question-papers

These  papers will help you to understand the types of questions which are asked in exam, you will understand the important topics which are covered in the exam by practising them, you will also get to know your preparation level .Best of luck for your examination.

Thankyou