See its very hard to define problems from NCERT and not from NCERT in subjects like Biology. But as per the experts and the toppers, 98% of the question in NEET comes from NCERT Biology. Thus you can see that there is a very good number coming from NCERT. Now from the past year analysis the weightage have been defined based on subject.

chapterwise weightage for NEET:

• Human Physiology and Genetics have maximum weightage in NEET.
• Diversity of Living Organisms has 14% weightage.
• Structural Organisationi n Plants and Animals takes 5%.
• Plant Physiology has 6% and Cell Structure and Function has 9%.
• Human Physiology has 20% weightage.
• Reproduction chapter has 9% and Genetics and Evolution has 18% weightage.
• Biology and Human Welfare has 9% weightage.
• Biology and its application has 4% weightage and Ecology and Environment has 6% weightage.

To know more about NEET chapterwise analysis visit the link below:

https://medicine.careers360.com/articles/neet-chapter-wise-weightage-and-important-topics

I hope this answer helps. All the very best for your future endeavors!