Government & Defence Entrance Exam

Candidates who have completed their degree are only eligible for the posts. After the completion of the degree, you can apply for the Sub-Inspector post. Eligibility:
1) Candidate must be a citizen of India.
2) Candidate must complete any degree from the recognised university.
3) The age limit is 30 years. And there will be age relaxation of 3 years for BC candidates and 5 years for SC and ST candidates. Selection:
At first, there will be physical tests for every candidate. The physical tests will include:
1) 5 KM running test.
2) Height and chest measurements. The candidate height should be at least 165 cms and chest should be between 181-185 cms. After meeting all these requirements, the candidate will be allowed to appear for the written exam. The written exam will be based on the following sections:
1) English
2) General Awareness
3) Reasoning
4) Numeric Ability
5) Logical Reasoning
Regards.

Please refer to the link provided below for a list of entrance exams conducted across the country for admission into BBA exams, and details regarding these exams. https://www.shiksha.com/bba/exams-pc-30
If you are interested in becoming an IAS officer then, you have to pursue your higher studies in Bachelor's degree courses like B.E. / B.Tech B.A. BCA B.Sc. B.A. , etc. , after completion of your 12th standard with Science stream from a Government recognised board. It is not mandatory to choose any particular subject in Graduation to become an IAS officer. You can opt for any stream of your interest in Graduation and after completion of your Graduation from a Government recognised university, you can apply for IAS examination. If needed, check on different papers for which you will have to appear in the UPSC examinations for selection to IAS and select an UG course which has those same subjects. Regards.

Hi Hari,
Here are the ways in which you can join Naval Academy:
1. NDA/NA entry- only male candidates are allowed for NDA/NA. Age limit for candidates is 16-19 years. Education qualification required is 10+2 with physics and maths subjects. To join the national defence academy (NDA), aspirants need to appear in written exam and in the service selection board (SSB) interview process which is handled by UPSC.
2. B.Tech entry- only unmarried male candidates are eligible to make use of this entry mode who are between the age of 16 -19 years of age. 10+2 Science stream with physics and mathematics subjects, with minimum 70% marks in PCM subjects and minimum 50% marks is required in English subject (10th or 12th class). This is a new entry of navy. SSB calls are made directly to candidates having the 12th percentage above the cut off percentage.
3. CDSE-male graduates who have done B.Sc. With physics and mathematics or Bachelor of engineering can apply for naval academy.
4. Other graduate entries- graduates and final year students are eligible to apply for this entry. There is no written test, the calls are directly made for SSB based on cut-off percentage of the qualifying exam. Age limit between 18-25 years is allowed.

I found these are the main and most commonly offered B.Sc. Subjects. Biology
Biochemistry
Botany
Chemistry
Computer Science
Electronics
Environmental Science
Mathematics
Physics
Zoology
And now these are the optional subjects available in UPSC Mains exam. Agriculture
Management
Animal Husbandry and Veterinary Science
Mathematics
Anthropology
Mechanical Engineering
Botany
Medical Science
Chemistry
Philosophy
Civil Engineering
Physics
Commerce and Accountancy
Political Science and International Relations
Economics
Psychology
Electrical Engineering
Public Administration
Geography
Sociology
Geology
Statistics
History
Zoology
Law
Literature of any one of the following languages :
Assamese, Bengali, Bodo, Dogri, Gujarati, Hindi, Kannada, Kashmir, Konkani, Maithili, Malayalam, Manipur, Marathi, Nepali, Oriya, Punjabi, Sanskrit, Santhali, Sindhi, Tamil, Telugu, Urdu and, English. Highlighted subjects are mainly available in Mains exam according to your B.Sc. Study. Regards.