can we select physics chemistry and biology as a three subjects for icar aleea and can by doing NEET preparation we can quality icar aleea?

Yes! And Yes! To both questions You can have Physics, chemistry and Biology/Agriculture, you can choose either Biology or Agriculture. All the best

Candidates should have cleared 10+2 or senior secondary examination from Central Board of Secondary Education or its equivalent with Physics, Chemistry and any one of the subjects from Mathematics/Biology/Home Science/Agriculture. So yes you are eligible to apply for ICAR entrance as per the criteria.
Yes incase you are preparing for NEET then that preparation is almost sufficient for ICAR preparation.

In biology, if all the chapters are read line by line from NCERT then maximum of the question can be done. Nothing special preparation you will require. NEET preparation should make your preparation strong enough to handle complex questions.

Good luck.