Of course you are totally eligible to write ICAR exam.

Icar have 74 agricultural universities. Icar has entrusted the task of conducting entrance examination to national testing agency. ICAR AIEEA is an all India entrance exam for various agriculture universities to get admission to 15% seats for bachelor degree in agriculture. It is conducted online mode and the questions will be multiple choice type. Candidates who have passed 12th with more than 50% marks from a recognised board are eligible to apply. You don't need to have Biology as a compulsory subject but along with the chemistry and physics you should have Biology or Mathematics. Since you are a pcmb student you are completely eligible for icar examination.

Stream A has three sections - Physics, Chemistry, Biology, and Architecture. If you have a clear idea about the fundamentals of these subjects then you can easily score decent marks with a few days of preparation. there is no need for you to prepare like neet examination. It only contains questions from NCERT textbook hence it is very important for you to be thorough with NCERT textbook of all the subjects.

As long as you are much familiar with the NCERT textbook it will be so easy for you to qualify the exam all the best.

Thank you.