Hello Anuradha..

Thanks for contacting Careers360..

There are certain corrections made in NCERT text books in Biology (+12,+11)..

Keeping the necessity in correcting the errors in some topics,the same was completed and circulated for use Some of the areas of connection are (1)Topic is Biomolecules and page number is 145 ,(2)in mineral nutrition in page number 202,(3) Structural organisation of animals in 109,and in 128,127,137it is Cells.

The +2 twelve classes textbook corrected topic is Environmental Issues in page 284.

As these were corrected,one who follows NCERT old Book, even in that position he or she need not panic and those who already are using the revised book are in the right topics or they can go for correct solutions as is found in NCERT system.

All the best:)

Hey,
Lately,NCERT books have undergone certain revisions. The revised edition of the NCERT books have some changes which will be incorporated in the next edition.
There are certain parts in both 11th and 12th have been changed.And if one is going to take NEET in 2019 or 2020 then one must be well aware of the changes made.
The following changes made in NCERT Biology are:
From class 11:
1.Biomolecules Pg 145:Skeletal Structure of Cholesterol is modified
2.Mineral nutrition Pg 202:Sentence is reframed
3.Structural Organisation in Animal Pg 109:Arrow placed correctly
4.Cell:Pg 127,128 and 137
From class 12:
Environmental Issues:Pg 273 and 284

Hope this helps.