Science

Hello,
I appreciate your interest to pursue Masters in science from Kolkata.
To assist you in choosing the top colleges to pursue the same, you can refer to the below mentioned link:
https://goo.gl/WWD69l
I hope it helps. If so, kindly upvote this answer. If you have any further questions, kindly revert.

Hello Rohit,
I understand and appreciate your interest in pursuing B.Sc in Economics. To assist you in choosing the colleges to pursue the same, kindly refer to the link below for more information on the colleges:
https://goo.gl/U7ZaU8
I hope this answers your question to your satisfaction. If so, kindly upvote this answer. If you have any further questions, kindly revert.

Yes, you can go for MBA in Health Management. But, you already have Masters in science. So, Masters in business administration is not looking in line with the past record. If you have a keen interest in Business, surely, you can go for it.

Admission in M.Sc degree at IIT is by examination JAM. There is no There is no age restriction of age for appearing in examination. You may refer to following link for further details: http://js2.iitd.ac.in/html/index.php

You can search about different books for NATA. Actually from this year, NATA has made changes in their syllabus, maths is included and scoring process is also changed. I think you should read multiple writers book to score good marks.

Biotech, Biochemistry or Biomedical sciences have excellent scope in India. Lots of positions are available for this disciplines in government as well as private companies.

Genetics is a good option if you are really interested in it. Or, go for chemistry as it has good scope.