What should i do? (biology)?

i am over halfway through my biology standard grade course, i am just going into 4th year of high school. Our teacher DOES NOT teach us what we need to know, he even teaches us the wrond stuff sometimes then when it comes to tests and our prelims he blames us for getting it wring when he didnt even teach us the stuf its asking for. basically hes a really bad teacher and just as an example last years standard grade class, out of about 20 of them only 2 past. I really need to pass my biology to get a job i want in the future, what should i do? does anyone know any online courses i could take so that i know everything or what? thanks