We all know you can't eat a mud pie, but did you know that without the soil that makes up a mud pie, we wouldn't have very much real food? We wouldn't have several important medicines, either! Soil is a very important resource. We walk on it, play in it, build with it, grow our food in it, and get antibiotics from it. But what exactly is soil? What makes it so important? Can we survive without soil? In Explore Soil! With 25 Great Projects, young readers learn what this substance is made of...