Direction Admission Process

Hi,
Refer to the link given below-
https://www.shiksha.com/university/techno-india-university-kolkata-38061/admission.

Which university are you asking about? Amity University Noida (Amity Institute of Organic Agriculture) offers B.Sc. (Hons. ). Agriculture without entrance exam. So you can apply here if interested. The eligibility criteria and selection process are given below. Eligibility criteria : 10+2 with PCB / PCM / Agriculture (min. 55%)
Selection criteria : For the time being Selection Process is based on video responses to the questions posted through the VIDEO LINK available on Admission Microsite.

As per the eligibility for M.Tech, you must have done either Btech or (Bsc+Msc), then only you can apply for M.Tech program. Since you have done B.Sc in Biotechnology, you further need to pursue Msc in any specialisation of Biotechnology
Yes, you can do m.tech after b.sc in maths. sit for gate, score good and get admission to the college of your choice.

The cut-off marks for IIT Roorkee MBA programme is based on the CAT percentile score, but the final admission is determined by the following: CAT Score, Academic Performance, GD and PI score, and Professional Experience. IIT Roorkee MBA cut off is decided by the IIT Roorkee admission committee separately for each year.

It's not possible. In order to get admission in any of the B.Tech programmes you need to appear for VITEEE exam and upon good rank you have to take part in counselling to get admission.