Asif, to be eligible for NEET, you should have completed your 12th with a minimum aggregate of 50% in Physics, Chemistry and Biology. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST. Now you should have had Physics, Chemistry and Biology as your core subjects in your 12th. Now if you haven't studied Biology as a subject in your 12th, you can atleast study Biology as an additional subject and then appear for NEET. Without this qualification, even if you apply for NEET, you may not get the admit card as you do not meet the eligibility criteria. You cannot attend counselling and you cannot get a seat without studying Biology.

Dear candidate, the minimum eligibility criteria for NEET is -

Candidates must have passed 10+2 or equivalent with Physics, Chemistry, Biology/Biotechnology and English as core subjects from a recognized board. Candidates who are appearing for the class 12 or equivalent exam are also eligible to apply for NEET 2020.

As per this you are not eligible to give NEET exam if you didn't had BIOLOGY as the core subject.

All the best

Hope this helps