So I am female and I call both female and male friends "dude" or when talking to a group, "you guys". Some people could take offence to it while others think it is ok. If you are not sure, just ask the person you are talking to if "guys or dude" is ok to say.
My guess would be each quatrain develops the problem of the poem and<span>the turn (volta<span>) comes at the beginning of the closing couplet.</span></span>