B.Sc

Here are the complete admission details for this college.
Kindly follow the link.
https://www.shiksha.com/university/Gujarat-university-Ahmedabad-29851/admission.

Instead of taking admission in B.Sc, You can opt for B.Voc Degree in Medical Lab Technology. B.Voc is a work integrated degree programme where applicants get opportunity to earn while learning. In this programme theory classes happen at International Skills Academy (training hub partner) and practic

No, you cannot use your PG marks. You should use your graduation marks.
Good luck.

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.