Hello student I'm sorry to inform you but no this is not possible in CBSE as CBSE does not offer on demand examination but you can appear in NIOS on demand examination and obtain the passing certificate of respective examination.

I request you to please help me with the examination in which you're willing to appear so that I can check and provide the details of eligibility requirements.

Feel free to comment if you've any doubt

Good luck

Hello,

If you had Biology as a subject in your +2 at the time of your passing, it can be possible. But if it was not at the time of your passing, it can't be possible.

You should contact your colleges authority regarding this to have a proper idea and guidance regarding it.