if i failed in biology but after improvement i passed with 56 and overall 65 percent can i gave neet?

Yes then it's allowed. The elibility criteria says ki candidates must have passed in physics chemistry biology separately and overall PCB for an unreserved general category should be 50% and above and I guess you are fulfilling both these criterias so yes you can give NEET and apply for medical colleges as per your NEET scores.

Best wishes. Thank you.