NDA

No, level of Mathematics in agriculture will be of elementary levels that is class 10th level.

Education qualification for NDA exam is that candidate have to qualify class 12th with PCM (Physics, Chemistry, Mathematics). Minimum Height of candidate should be 157 cm for Navy as well as Army. For Air force, Minimum Height required is 163 cm.

NDA is the best without any second thought.

Yes, he can apply for NDA examination. According to the eligibility criteria, the Minimum height required for Air Force is 167 centimetres while the height required for Navy as well as Army is 152 centimetres.

To get admission, candidates have to pass the Preliminary Test and the Final Workshop. Candidates have to appear in all rounds organized by the authority to get admission in its arts related courses. Here, candidates can get the NSD 2019 complete details.
Reporting at NSD campus: 2nd week of June.

Hi,
For NDA, you have to give NDA exam that is conducted twice every year, and if you clear that written exam after that you have to appear for SSB (it is an interview process), and also have to clear that and then after that you have to clear physical and medical test. If you clear all these stages you can join NDA.

Please refer to the links below for cut-off details:
https://www.shiksha.com/exams/nda/cutoff

Yes, there is an age criterion:
Minimum Age: 16.5 years
Maximum Age: 19.5 years.

To know about every detailed information about NDA exam, refer the following link:
https://www.shiksha.com/college/nda-national-defence-academy-Pune-53488