Dileep, ideally to study MBBS, you should have been a Biology student. Meaning you should be studying Bi.P.C. Now if you are a MPC student, you can take up Biology as an additional subject and then score a minimum aggregate of 50% in Physics, Chemistry and Biology in your 12th. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST. If you can manage this aggregate, you are eligible for appearing in NEET thereby clearing the first step to.studying MBBS.