The mouth is one of the best human habitats on the body! In other words, your teeth aren't the only inhabitants of your mouth. In this book, readers learn more about the microscopic organisms that make their home in the mouth-both welcome and unwelcome. Full of simple diagrams and interesting information about this part of the human body, this volume engages readers looking to supplement their science classes with a colorful layout and friendly guides through this often-used part of the human body.