Did you know with questions and answers

"In this book you will find all the answers to the most surprising and fascinating questions. · What is the longest river in Europe? · How much would you weigh if you were on the Moon? · Why is sea water salty? · What is a pachyderm? · What is the human body made of? · What did Archimedes discover? Have fun learning new facts and testing yourself and your friends." -- Amazon.com.