B.Sc

Yes, you can take B.Sc. Nursing after passing the 12th.

A very precise cut off can't be given, as online application has paved the way for more applications and this is the first post pandemic 10+2 exam, so cut-offs are different. In my year, I scored 95% total and 97 maths, and I got chance in the 9th list. Scoring over 90 is being safe, though 80+ scoring students have also got chance in later lists.
Update- today, the education ministry of state declared that from 18th july- 5th August, colleges will operate their admission portal and the fees of application is waived. So there will be more competition.

Yes there are placement in B.Sc. Agriculture field the placements students gets through college are 70-90% the placements through agriculture can get in agricultural journalism, in banking sector, also as an consultants, students also can give various competitive exams.

The management of the Joint Admission and Matriculation Board (JAMB) has announced 270 and above marks . It is the latest JAMB cutt off mark for Nursing Science. This cut-off mark has given for the year 2022 & 2023.

The total fees at Shri Haygriv Ramanuj Sanskrit Mahavidyalaya for B.Sc in Computer Science is about INR 90,000.

Candidates must have cleared their Class 12th in Science subjects with a minimum percentage of 50% to 60% aggregate marks from a recognised board for admission in B.Sc. You can also refer from this link- https://www.shiksha.com/university/delhi-university-du-24642/courses/bsc-bc.

Course Fee for B.Sc. for major subject is INR 6680/- for each semester. You can also refer from this link for more information- https://www.shiksha.com/college/anandaram-dhekial-phookan-college-nagaon-64863/courses.

It is around 1.5-2.5k per year

There are many colleges for B.Sc and B.C.A in Chennai we can list some top colleges for your better understanding. It's you choice which to select there some list of colleges
BCA colleges in Chennai
1. Loyola College, Chennai
2. Womens's Cristian College, Chennai
3. Presidency College, Chennai
4. Stella Maris College, Chennai
B. S. C college in Chennai
1. Guru Nanak College, Chennai
2. Loyola College, Chennai
Note:-Student should get minimum aggregate of 50% in class 12th.

There are many Institutes and colleges of B. S. S in Medical Science there some similar colleges of your suggestions
1.Chandigarh University, Chandigarh.
2.University Of Mumbai [MU] Fort, Mumbai
3.DAV College, Chandigarh Chandigarh