$5 says this's been brought up alot, but "7 Nation Army

Hey, a few questions about Seven Nation Army by the White Stripes:

-How do you get the distortion effect on the chorus?
-Can it be played just as effectively with a breathing bassist instead of the bass track the band itself uses?
-Is it played with power chords? (pretty sure about that one but wanted to make sure)
-Can the bass riff be substituted on guitar?

Thanks!