I’m doing a paper on bow hunting, I was wondering if you can tell me why you guys use bow and not gun.

Every bowhunter hunts for their own reasons so I can only speak for myself personally.  I bowhunt because it's more challenging and you have a closer personal connection with the game you're pursuing.  The feeling of accomplishment harvesting an animal with archery equipment is much more than with a gun - for me anyways.  Also, archery seasons are much longer than most firearms seasons which means I get to spend more time in the woods each fall.