apple care warranty!!!

is any of apple user what does apple care covers?

my cousin has the apple care before. and her charger is broken. so apple replace a new one for her. that really nice. and i do have the macbook pro 15'' and im just wondering what exactly does apple care cover for my macbook pro's warranty. what if the screen, ram memory, battery or hdd broken. do apple care replace a new one for me or fixed the hardware. i don't want to spend 220s just cover for the charger. i really need to know about the apple care what exactly of warranty they cover. my one year warranty almost expired. so, if anyone know about it. please gimme the full description. im really appreciate that.,,,

thanks all