Hello,

Yes, you can do 12th again from Biology side through MP Open Board. Your Commerce marksheet will still be valid, no issue with that.

You will have to give exams for all Biology stream subjects. Usually, it's 5 main subjects.

In future, having two 12th marksheets is not a big problem, but you should use only one marksheet for higher studies or job. Use the one which suits your career path.

Just don’t use both at the same time anywhere. That can create confusion.

Hope it helps !