Science

Forensic science is basically using the principles of science to solve and analyze criminal cases, whereas psychology is mostly the study of the human mind and tries to determine the psychological factors which lead to the crime. Both of them deal with the legal system but employ different methods in their application.

Different subjects you can opt for to pursue a career in astrobiology are as follows:
1) Physics
2) Chemistry
3) Maths
4) Biology
5) Geology
You could also try for a course in astronomy and space research from recognised institutes in India or abroad.

Please get in touch with your institute for this query. Many colleges do not offer any exams after you have completed graduation while others may offer an improvement exam for a small fee.

You could take up a number of courses after completing B.Sc in Biology. Some of the subjects you could pursue after completing your course in Biology are as follows:
1) Master of Science in Biology
2) Master of Science in Biological Sciences
3) Master of Science in Applied Biology
4) Master of Science in Environmental Biology
5) Master of Science in Environmental Microbiology
These are only a few subjects you could pursue in M.Sc. from a much broader pool of subjects. I am certain that if you do well in your studies, you will get a respectable package in the industry.

Some of the better colleges to pursue M.Sc in maths through distance learning are as follows:
1) Bangalore University
2) Guru Nanak Dev University
3) IGNOU
4) Madras University
5) University of Mumbai

Mathematical science means science over mathematics, but in mathematics (Hons), you have to study the higher mathematics.

Yes, you can go for M.Sc, but I would suggest that you should go for M.Tech that is a better option.
Good luck.

Your basic qualifications just provide background. The remaining things are to be added. It depends on your interest, solely. Moreover, training yourself goes on lifelong. You can pursue a management course. Work for a career and you will succeed.