Can i go from a C to an A in A - level?

I got a 37/90 in AS and i need a 72/90 in A levels to secure an A. is it possible? my main concern is essays as we really don't have a proper teacher in school that teaches us how to write and structure essays. also if anyone has model answers please do send them as im desperate atp lol

I got a U in chemsitry in year 12 and ended up with a B. It’s definitely possible. I didn’t do essay subjects but I know there’s a lot of online resources and YouTube videos and such. Is there any other teacher in the department or who teaches a subject that has similar structured essays that you could ask? Could you talk to students in your class that scored higher than you?