Everything around us is made from the Earth. Some things are easily replaced, while others are not. Think about the food you have eaten or the energy it took to zoom to school on the bus. What natural resources have you used today, and are they easy to replace? Step through the latest book in the Compare and Contrast series to learn about the world's resources, how long they take to reproduce, and how technology and ingenuity are helping to relieve the strain on some of our most precious reserves.