Class 12-science

If you had taken up sciences in 10+2, then engineering or medicine or Bachelor of sciences (Physics, Chemistry, Mathematics, Computer Science, biotechnology, IT, electronics etc. In various permutations and combinations of subjects) or even BCA. These are some obvious transitions.

Yes, of course you'll be eligible to do that. You just need a Bachelor's degree for UPSC. Be it a 4 year programme or 5 years.

Hello Dear, You have just completed 12th. You will have to go for graduation. So don't make a time table for UPSC now. Whenever you get some time, do revise all the topics of History, Geography, Political Science that you have read in your school. Now come to the current affairs section. Do read some newspaper, read the important exam oriented issues. This will definitely help you to score a good mark in UPSC.

Hello Dear, Recruitment for IAS and other all India Services is done through UPSC civil service examination. For UPSC you need to be a graduate from UGC recognised institutions.

Hi Prabhjit Singh,
For career advice, kindly click the link below to know the career choices after class 12th (non-medical).
https://www.shiksha.com/courses-after-12th/science.

The chances are very less because your academics are very bad and aeronautical engineering is too difficult. If you are interested in aeronautics then you can write it again, otherwise, you can prefer any other branch.

Yes, 12th pass out students can easily pursue computer science from Ravenshaw University.

In Science you have Engineering, Medical entrance examinations. Or you can go for B.Sc. You can also choose B.A. If interested in Astrology.

You can go for hotel management from good college.

You are eligible for entrance exam. You will have to qualify in exam to get admission in Amravati University.