I am having a bit of trouble seeing what you're getting at as it seems these are thoughts just rolling around in your head? Either way, i want to help. So, to clarify, you are having trouble with the discussions and the essay and as a result you would like a different instructor or you may just be getting out of the M.A program because now you're thinking of a different career path right?
^^^ if that is the case...i can say that a different instructor (if that is even an option) won't change your situation. the book will still be the same and the material is fairly in-depth. the discussions really are there to help you out and the essays will prepare you for the psychology and other sciences to follow (it seems the sciences are very big on research projects, essays and discussions). with the discussions you get to see others' answers and i recommend adding points others have included in theirs to your notes, paying attention to how they are worded and then comparing it to your own. Also, the biology is just the beginning i think...in the next semesters there will be Anatomy and physiology 1 and 2 which seems even more in-depth, there will also be nutrition i believe which if you pay attention to the bit of nutrition in the bio book, i can only guess its, just a pre-cursor to what's to come. if you think about all this at once it seems overwhelming, but this is a self paced program...so you get to take it one step at a time and move to the pace that best suits you. i can understand the urge to want to finish this and have your career right away but in order for it to be enjoyable or even understandable for the majority...we have to pace ourselves. graduating with a 4.0 is worth the wait. If you're think of another career, maybe that is where you may be happier heading? it seems you're already stuck in the bio right now so the only option if you don't want to loose your money is to finish it along with the semester and transferring those credits to the career you're looking at if they can be transferred? you may also need to contact the student services and speak to a education counselor about it...maybe there is another option for you that we're not seeing?
P.S. i know a few students on here including myself wouldn't mind helping out. what exactly are you having trouble with in the discussion and the essay? like is it formatting, structure or material related?