Discovery Channel host and acclaimed writer Jay Ingram helps you find the answers to questions you've never really settled, like “What is déjà vu?” “Why do we blink?”, “Why are yawns contagious?” and the perennial “Do we really use only 10% of our brains?” Note that this book is a combined and abridged edition of The Science of Why and The Science of Why2.Have you ever wondered if people really do weird things during the full moon? How about whether fingernails grow faster th