Hi,

As per the Eligibility criteria of NDA-NA Exam, to get into Air Force and Navy, student should have Passed XII from recognised Board with Physics and Maths. So, if you belong to Biology section and don't have Mathematics as an additional subject then you are not eligible to join Air Force or Navy through NDA-NA Exam. However you can still Join Indian Army.

I hope this will answer your query.

Thanks!!!

As per the eligibility criteria laid out for NDA you need to pass class 12th board exams from any stream to be eligible to join the Army wing. So being a Biology student, you are eligible to join the Army wing through NDA.