im in 11 and i pursue diploma in biotechnology after 12.is there any entrance exam for that?what are the sub groups of biotechnology?

For Diploma in biotechnology you have to give the state polytechnic entrance examination in ordered to enroll that course. The subject group required for Biotechnology are PCB and if you have mathematics then it will be a instrumental. If not then doesn't matter.

As you haven't mentioned the name of your state then its hard to inform you about the examination corresponding to your state. Also some private colleges may also conduct there own entrance examination for the admission to the course.

I hope my answer helps. All the very best for your future endeavors!