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Candidates applying for the CG PET exam must have passed 10+2 or equivalent examination with Mathematics, Physics as compulsory subjects and Chemistry/Biology/Biotechnology/Technical vocational courses as optional subjects. Candidates applying for the B.Tech Biotechnology must have studied Biology instead of Mathematics in their 10+2. for much more information check the below link

https://engineering.careers360.com/articles/cg-pet-eligibility-criteria