AHSEC

You still can repeat class 12th board, if you want to if there is not more than 2 or 3 years gap between 10 and 10+2 you are repeating. If there is a long gap i.e., more than 3 or 4 years then maybe you have to first give 10th board exam and then later the class 12th board exam.

Not at all, you do not need to do any work. There is no negative marking in boards examination, so you do not need to worry about this and just focus on your next paper now all the best
Is about putting the wrong number of answer it could happen so don't worry no marks will get deducted.

No, there is no problem at all in your improvement examination. Contact your regional head Office for clear and accurate knowledge about examination. Hope it will help you.

Hello,
Please go with this college predictor this will help you to choose best for you
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Thank you.

If you have good score in JEE Advanced, you can apply for other top colleges other than IITs which accept JEE Advance score.

Yes, you can go for improvement exams because the minimum eligibility criteria is for getting admission in IITs, NITs and GFTIs is 75% in 12th class. Or, you should be in top 20 percentile of respective board.

You have to pass the minimum criteria required to get admission through JEE Mains.