Microbiology

If you know Programming skills than okay otherwise join any course with Basic for Ethical Hacking. A Hacker must be a computer systems expert and needs to have very strong programming and computer networking skills in the long term but you can start practising with simple tricks.

Yes, You should continue M.Sc in bio-tech. There is no age limit for M.Sc. Okay. You want to get admission in M.Sc. You apply for IIT JAM and well prepare for it. If you get a better score. You eligible for IIT college in India or IISC and IISER. These colleges give admission by jAM only. Okay If you don't interest to write jam then some college conducting there an entrance exam for M.Sc. You continue M.Sc with those exams also.
All the best. Hope this helps.

There are placements for B.Sc Biotechnology at GGDSD College. The placements are not for biotech or microbiology or IT or any course of under BSC, It is for the complete batch of B.Sc.