Career Options after 12th Science are as follows
BSc (Hons) : Indian universities offer BSc (Hons) to students who have passed 10+2 with Physics, Chemistry, Mathematics or Biology. Later you can go for a masters degree and work as a junior research fellow in any research institute. You can join as a lecturer in any university or have opportunity in chemical industry, pharmaceutical industry, or in government organizations.
BTech/BE: Engineering is one of the Career Options after 12th Science. You can appear for all the engineering entrance exams both at the state level and at the national level for admission to BTech programs. You should be 12th with Physics, Chemistry and Mathematics as main subjects.
MBBS / BDS : MBBS is definitely one of the best Career Options after 12th Science and become a qualified doctor. You should be 12th with Biology or Life Sciences as one of the core subjects. Entrance exams are held for MBBS/BDS programs in both at the state level and at the national level.
BCA: If you want to build your career in the field of computer applications, then you should go for Bachelor of Computer Applications (BCA). Later you can go for MCA. You should be 12th in any stream with Mathematics and English as core subjects. Entrance tests are conducted in individual colleges for admission to BCA.
BA / BSc Economics: Most of the colleges offer a Bachelors degree in Economics, it may be a BA degree or a BSc degree. Universities like the University of Delhi offer a BA degree while others like the University of Mumbai and the University of Calcutta offer a BSc degree. You should be 12th pass with mathematics and English as core subjects. Some universities hold entrance exams where concepts of Mathematics and English are tested.
B.Sc. (Computer Science): As a science student you can pursue a BSc in Computer Science. You should be 12th from any stream with 60% marks in Mathematics.
B Pharma: B Pharma is one of the important options for students who have done 10+2 in science. B Pharma is usually a 4 years degree course and students who complete B Pharma can register themselves as pharmacist. After completing the course, you can work as pharmacist, drug inspector, drug therapist, health inspector, or as a drug technician. You should be 12th with Physics, Chemistry, Mathematics or Biology as core subjects.
BBA: you can do Bachelor in Business Administration (BBA), if you have Mathematics and English as core subjects?