Hello , 

As per your query is concerned that due to some reasons you want to apply for your improvement exam in 12th standard and you want to know whether you have to give practical exams or not. I would like to tell you that the improvement exam has nothing to do with your practical exams therefore what ever you scored in your practical will be carry forwarded with their improvement marksheet so you don't have to worry or panic about your practical exams all you have to do is just to prepare for your improvement exams only. 

I hope your query is solved. 

Thank you.