CAN I APPLY IMPROVEMENT EXAM FOR ONE SUBJECT IN ISC?
Yes friend you can definitely give improvement exam on one subject or on any number of subjects which you wish.
As far as I know June is the last date to register for the improvement exam.
You will have to give a written application to the Principal of the School, who will register you online for the entry to the ISC Examination.
If you want more details you can send e-mail to the council. The email id is council@cisce.org They help you real quick.
Good luck :)