Hello Ankit,

Yes, You can write NDA  Exam after completing 12 with biology but 

you will be only eligible for the Army wing not for the Airforce or 

Navy,as their eligibility criteria is candidate should have

Mathematics and Physics in 10+2.

You can also visit the careers360 link regarding it-

https://competition.careers360.com/exams/nda

Thank you.

hope it helps you.

Hey Ankit,

Educational Requirement for NDA is

For Army Wing of National Defence Academy - Candidates applying for admission to the Army wing of National Defence Academy should have passed Class 12.

For Air Force and Naval Wings of National Defence Academy and for the 10+2 Cadet Entry Scheme at the Indian Naval Academy - The candidates must have passed class 12 with Physics and Mathematics conducted by State Education Board/ University. Candidates appearing in Class 12 or equivalent examination are also eligible to apply for NDA 2019. However, those appearing/ passing class 11 exams are not eligible for the exam.