Simply if the Biology: The Living Environment Regents is canceled no one in that school can get an Advanced Regents Diploma. However to get a basic diploma you only need to pass one science regents.
For an advanced diploma you need 2 science regents one life science regents and one physical science regents and 3 years of high school science where one year must be living environment. The last year does not need to be a regents course, it could be an AP or a science, technology or engineering elective.
I have link for the state requirements to pass regents in New York State available if the Moderators let me post the link I will.
I teach at yeshiva and public school for a living for all 3 math regents and for all 4 science regents.