What are the subjects I should take in last year of IGNOU BSc (in Zoology) since I'm preparing for IIT-JAM Biotechnology?
Since you wish to appear in iit jam you need to have two science subjects as your subsidiary in two consecutive semesters.
In this case you could take chemistry for two semesters and botany for other two.
Remember this eligibility is compulsory of having two additional science subjects for iit jam.
All the best