Can i give National Science Olympiad of 12th class as i am actually passed 12th class but i will give improvement exam for 12th .
NO you are not eligible for national Science Olympiad of class 12th as you have said that you have passed class 12th and you will give Improvement Exams now. So, national Science olympiad (level 1) exam can be given by only those students who are in class 1 - 12th.
You must have to be in class 12th or yet to give class 12th to be eligible for National Science Olympiad (Exam).
Further, to know more about the national Science Olympiad for more details, you can follow below mentioned link to know more : https://school.careers360.com/exams/nso
i hope that this will help.