Explain There are two doors and there is one guard for each door one door leads to life and the other leads to death you have only one question to ask and one of the guard tells only lies?

Walk up to either guard and say to him: "what would the other guard say if i asked if this door leads to life" if he has it isn't life then it really is, one guard lies and one tells the truth, the one that lie's will always lie, and the one that tells you the truth is telling you what the one lying would say, so what ever they say would be a lie, so just go with opposite of what ever they say