He's beheld the butt and offered the scoop on poop. Now Artie Bennett takes young readers on a discovery of those little (and not so little) puffs that exit from our mouths and duffs--the burp, the belch, and the fart! With Bennett's signature combination of real science and zany rhyme, kids will learn the how, why, and where of gas-tastic eruptions made by people and animals, such as: * why…