Hi there, 

Thank you for posting your query on our platform. 

To answer your first question, after completing your B.Tech degree that is after completing your graduation you can write the various LLB entrance examinations of different Universities like Delhi University, Maharashtra University, Allahabad University, Banaras Hindu University, Osmania University etc. 

Cracking this examination you'll get admission into a college recognized by the Bar Council of India for Legal studies and at the end of the three years of course you will get a LLB degree. 

For further information I am attaching the link of Delhi University LLB entrance exams details kindly refer to this to have a better idea regarding the intricate and important details of the examination: 

https://law.careers360.com/exams/du-llb

To answer your next question, with a graduation degree in Biotechnology after completing your LLB and after clearing the All India Bar Council Exam you can opt for Masters i.e. LLM in International Environmental Law. 

There will be various options of LLM available to you; the most basic being criminal law, constitutional law, human rights, etc. I have answered above keeping biotechnology in mind. You obviously have the freedom of choosing any course. 

Once you get into LLB, you'll understand the intricacies of all aspects of the related subjects of legal studies which will surely give you a better idea of choosing the suitable course for LLM. 

Hope this helps. 

Wishing you luck!