B.Sc Computer Science

Yes, after B.Sc, you can do M.Sc. In computer Science or MCA if you want to go in teaching line then go for M.Sc. Or, you are having interest in developing software then go for MCA.

Yes, you can go for Masters aboard after doing your Bachelor's degree in India.

There is increasing awareness on environment and everybody is looking for remedies in diseases. Researches are made in pharmaceutical industries, hospital labs etc. So, the job opportunity looks more in the arena of microbiology.

Both microbiology and CS are have a good career. It should depend on your interest which ever course you take you can be successful. All the best.

Well, there is no age to study but still, I'm not sure whether you will be allowed or not. The best person who can help you with this is the college authority from where you are planning to do it.

Yes, you can get admission without having chemistry.

Hello Digvijay Singh,
The placements opportunities for BSc are less compared with engineering or management graduates. However, you have done BSc in computer science and hence, I feel, you have a great chance of getting job via placements. On top of it, you are studying in Christ University which has reputation of having a very good placement cell. I feel, you will get good employment via this placement cell of the Christ University.
Best wishes to you.