Government & Defence Entrance Exam

You can have any subject like Arts, Commerce, Science or engineering in your 12th class and graduation but you have to qualify the written exam and SSB for that.
To get selected as an Army Officer you must qualify one of the following exams:
After 12th - NDA followed by SSB
Or
After Graduation - CDS followed by SSB
Or
After Engineering - Direct SSB
Or
If you are NCC 'C' Certificate holder then you can directly appear for SSB interview.
All the best.

Educational requirements to take navy exams are:-
NDA : 12th
CDS : Graduation

You should plan in a systematic manner for IES exam. You should devote daily 2 hours for current affairs and GK preparation. Also, devote 3-4 hours for your main subjects preparation.
All the best.

Depending upon your interest you can choose any subject from English, history, geography, political science, economics, sociology etc. Most of these subjects are useful in preparation for IAS/PCS and other competitive exams after graduation.

You must focus on general knowledge, current affairs, essay writing and detailed study of your choice of 2 subjects. Basically, you need to qualify the Civil Services Exam which you can appear after completing graduation. The percentage in graduation does not matter much for appearing and qualifying in the written exam for civil services, however, it carries judgmental value in the interview.

Hello Abraham Khan,
As you want to know about the better profession in terms of salary then loco pilot is the best option, they get a high salary because their job is bit risky.

You are eligible to join as an airman in technical streams of Indian Air Force subjected to meeting other criterion. You are not eligible for Commissioned Officer job in IAF based on your current educational qualifications.

B.Sc in life science can apply as a research associate in agriculture, biotech and lab assistant in various government laboratories.

As a B.Com student, you have to build up your foundation by studying basic books like NCERTs and GK Lucent.