Maths Spl

Yes, you can go for B.Tech Biotech and one of the best universities for that is Bennett University, Gr. Noida.

You have not write about the college/university name. However, the basic eligibility criteria for 3 years LL.B. Regular course is a Bachelor degree in any discipline with minimum 50% of marks for general, 45% for OBCs and 40% for SC/ST candidates. Therefore, you can be eligible if meeting the above

The criteria depends upon the college/ institute/ university you are pursuing your B.Sc. Maths programme from. If there is a process to transfer your programme to the other course, then you need to contact the admissions department of your respective college in order to change the programme.

It will depend on institutions. Information related to the admission procedure is available on the college website.For more details, you can refer the below mentioned link:
https://www.shiksha.com/science/course/b-sc-in-mathematics-jadavpur-university-jadavpur-kolkata-273121

The eligibility criteria of DSSSB TGT Maths is given below.
1. Educational qualifications : A Bachelors Degree or equivalent with at least 45% marks from recognised University in the concerned subject.
2. B.Ed. From a recognised university
3. Pass in the Central Teacher Eligibility Test (CTET)
So from

You have to opt for National Institute of open schooling (NIOS). Here you can do the class 12th with Maths and Science as per your needs. However you can not change your stream during the current academic session.

Since you have statistics of all three years, you can apply for M.Sc. Statistics. Aggregate marks are 50% overall and 60% in statistics in your graduation.

I think you should go with B.Sc. Statistics, because B.Sc. Data Science students have big competition with B.Tech CSE students and most of the companies prefers to select the B.Tech CSE students in place of B.Sc. Students.