Science

Hi, Admission in B.Sc Hons is based on marks in three subjects
physics+ mathematics+ chemistry/ computer science. You will get admission in Delhi University but maybe not in the North campus if you belong to general category.

Yes, you can get in top colleges to pursue B.Sc in mathematics.

Hey,
You can apply application form online from Delhi University website for under graduation courses under graduation portal.
The portal is going to live this week.
Stay updated through the university website.
For more information regarding admission process, visit Delhi university website.

Generally to pursue higher level programs, the minimum percentage in 60 percent in some colleges and for top institutes, it may go up to 70 percentage.

Hello,
You may refer the link below to know the colleges for B.Tech biotechnology in Kolkata:
https://www.shiksha.com/b-tech/colleges/b-tech-in-biotechnology-engineering-colleges-Kolkata.

Hi, Eligibility Criteria. Candidates holding Bachelor's degree in relevant disciplines such as Engineering, Pharmacy, Criminology, Forensic Science and Science are eligible to pursue this course. Minimum aggregate marks required is 45-55% marks.

Yes, Maths is a must for Economics (hons.) in Delhi University.