a blond a brunet and a red-head are in the desert. each of them has something to help them on there journey.

the brunet has a sandwich in witch she explains, "in case i get hungry, ill have this pp-n-j"

the red-head has a bottle of water and explains "in case i get thirsty i can have a drink!"

the blond has a car door... this confuses the other two and they ask... why the door of all things? the blond explains calmly, "well... in case i get hot, i can roll down the window"