MACBETH HELP PLEASE! i don't understand what this question is asking me..?

its a really shitty question and your teacher is an idiot, but basically they want u to tell how macbeth's character changed and why. I think the "how it is believable" part is basically just asking you to give reasons as to why he changed. Like he went from humble to power hungry because the 3 witches told him he would be king and he then made it happen