B.Sc

You would be eligible for most colleges as PCM are three main subjects which you need to study at 10+2 level. Please refer to the link provided below for a list of top colleges which offer courses in B.Sc. Biotechnology in India:
https://www.shiksha.com/science/colleges/biotechnology-colleges-india

Some of the best colleges offering B.Sc. in Agriculture are private colleges. Faculty of these colleges are quite experienced and know their subject. Please refer to the link provided below for a list of top private colleges which offer a course in B.Sc (agriculture):
https://www.shiksha.com/science/colleges/b-sc-agriculture-colleges-india

Please refer to the link provided below for a list of colleges offering a course in B.Sc (Medical Imaging Technology):
https://www.shiksha.com/medicine-health-sciences/paramedical/colleges/colleges-india?uaf[]=specialization&ts=15020154&rf=filters&sp[]=433

Please refer to the link provided below for details on getting admission in Chandigarh University in B.Sc. agriculture:
https://www.shiksha.com/science/course/b-sc-hons-in-agriculture-chandigarh-university-245052

After completing your B.Sc in Mathematics, you could pursue a course in M.Sc Astronomy from some of the top colleges in India. This would open up a number of avenues for you in this field. B.Sc. in Mathematics should help you as Mathematics is a major part of astronomy and space research. If needed, you could plan for a PhD in astronomy and become a teacher in this field.

Please refer to the link provided below for a list of top colleges offering courses in B.Sc. agriculture in Jaipur:
https://www.shiksha.com/science/colleges/b-sc-agriculture-colleges-jaipur

If you are targeting Civil Services Examination conducted by UPSC then based on records of successful candidates and thier subject selection you may choose BA over B.Sc

You can go for Master's degree in biotechnology. You can get a very good job after M.Sc.

The eligibility criteria for IX-XII class teacher:
Clear post-graduation in any stream which you can teach in school.
Clear B.Ed from a recognized college.
After completing your graduation you have entrance exams like:
UPTET
CTET
JNV
KVS