Hello Aspirant

If you have scored less in your 12th due tio 1,2 subjects and you want to improve your marks in it,Yes you can do so by giving and improvement exam

In this exam

Let us suppose You have got 40/80 in Physics and in improvement you get 60/80 then the previous marks will be updated by the new score,But if you score less that what you scored before the marks will stay intact

Yes you can repeat your 12 th all over again

Regards!