B.Sc

Yes, you are eligible to take admission for both the courses.

Kindly visit this link:
https://www.shiksha.com/it-software/course/b-sc-in-computer-science-srm-institute-of-science-and-technology-Chennai-kattankulathur-campus-kattankulathur-266599

Yes, this course is approved by RCI.

Kindly visit this link:
https://www.shiksha.com/science/articles/bsc-in-agriculture-course-career-scope-and-salary-prospects-blogId-14705

Placements are not so good. You need to work very hard.

You can do graduation and get a good job in radiology. You just have to have good knowledge of this course. So, be prepared.
Good luck.

Hi,
What you basically want is a migration. For migration, it depends upon college to college. Some colleges give migrations and in some universities/colleges like AMU Migrations are not allowed. Some allow inter migrations and some limit to intra migrations. You have to check what your college policy is.

Hi,
Since you have not filled the form this year you cannot appear this time. But, you can appear in the entrance exam next year. You have to score good rank to get admission.

Hello,
Yes, it is possible to do B.Sc Zoology on the basis of your class 12th, if you had biology/biotechnology as a subject and good marks.

Hi,
The migrations are generally done in the second year. But, the policy may differ from college to college. Some may allow it and some may even not permit migrations at all.