Central Board of Secondary Education
Class – XII (Year 2011)
Subject – Biology - (Set- 3)
All Questions are compulsory.
Wherever necessary, the diagrams drawn should be neat and
Q.1 Mention how is mutation theory of Hugo de Vries
different from Darwin's theory of natural selection.
Q.2 Why are some organisms called as eurythermals and
some others as stenohaline ?