Hi Aspirant,

In NEET, questions are asked from different sources & there's no strict rule that questions will be asked from a specific book for any subject, may it be, physics, chemistry or biology but still relying on the NCERT book is always a good option.

Going by last few year's question papers, more than 50% question can be expected from NCERT for not only biology but also the other 2 subjects so it is recommended that you be thorough with the entire text & please make sure to revise the NCERT at least thrice.

Good luck!