CBSE 12th

It's seems to be a little bit difficult as your score is 50 but it requires 55% for getting admission.

It may be difficult as your score is 50. They require 55% for admission.

Yes, after it because aggregate marks the college needs is 55%. After that, you will be able to do BBA.

It's clearly mentioned in IISER website: (https://www.iiseradmission.in/).
The easiest way to get direct admission is to pass for the KVPY exam. Otherwise, you can have a look via
JEE Advanced (ranking below 10,000), State and Central Boards Channel (SCB) channel.

It's not that simple unless you are looking for a private college. For government colleges, it solely depends on your marks from engineering exams like KEAM for Kerala, JEE Mains and JEE Advanced. In private colleges, you can actually get direct admission.

Hello,
Eligibility for B.Sc. In Nautical Science. As a minimum criterion of eligibility, the course requires the candidate to have attained the 10+2 qualification in the Science stream with Physics, Math and Chemistry as main subjects, and a minimum aggregate score of 60%.

Well Komal, I am sharing some Info with you. Go through it and check out the eligibility criteria:
Course Level Diploma
Duration 2 years
Examination Type Semester System/ Year wise
Eligibility 10+2 with minimum 50% marks in aggregate with Science subjects
Admission Process based on entrance exam
Course Fee INR 10,000 to 5 Lacs
Average Starting Salary INR 3 to 20 lacs per annum
Hope this will help you.
Best of luck.

Here, the best courses for you:
1. Bachelors of Commerce (B.Com)
2. Bachelors of Commerce (Honours) or B.Com (Hons)
3. Bachelors in Economics
4. Bachelors of Business Administration (BBA)
5. Bachelor of Management Studies (BMS)
6. Chartered Accountancy (CA)
7. Company Secretary (CS)
8. Cost and Management Accountant (CMA)
9. Certified Financial Planner (CFP)
10. Bachelor of Law (LLB)