Colleges in West Bengal

As your marks is very Low in your B.Sc. You may find it difficult to get some college still some college takes admission with this grade also. You can see Lovely Professional University, they conduct their own examination. If you score good in that, you can take admission.

Yes, you can definitely get biological science considering the result of class 12th.

Hi, the admissions to BBA are not done on the basis of merit but on the basis of entrance exam. For instance to get admission in DU for BBA you have to appear for entrance exam i.e. JAT etc. It varies from university to university.

Management Quota:
You just need pass marks in 12th board and NEET qualification marks to get a direct seat through Management quota in India. Colleges like KIMS, Bhubaneswar. Katuri Medical College, Guntur, Annai Medical College, Kanchipuram can offer seats at low rates, however, all the medical colleges provide the same syllabus as given by MCI ( The Medical Council Of India). However, there is a risk involved and it is best if you avoid securing a seat via the management quota. Last year more than 500 such admissions were cancelled by the Medical Council of India. The choice is yours.
Good luck.

Admissions are not open yet. Please keep a track of the official website for updates.
Link: http://blis.wbnsouadmissions.com/

Candidates who obtained at least 50% marks in postgraduate course in Science, Arts & Commerce preceded by regular Hons. Degree in relevant subject.
Please refer to the link to know about the fee structure and refer page 5: http://www.klyuniv.ac.in/upload/news/fees schedule2016-17 KU_19.07.2016.pdf.

Now a days, the craze of engineering is very low. So, you can convert at the first counselling and not wait for the second. I think you can, but chances are low.