A Scholastic Level 2 Reader that answers early readers' questions about rocks and minerals! The whole world is made of rocks! The Earth's rocky crust was formed millions years ago, and its rocks are always changing. It is full of fascinating minerals, and we use its treasures in hundreds of ways. Did you know that toothpaste contains finely ground rock dust, that the stripes in the Grand Canyon's rocks were once layers of sand at the bottom of the sea, and that robots are examining the rocks on Mars? This Level 2 Reader teaches readers all about the different kind of rocks and minerals, how rocks were shaped, how we use the Earth's mineral resources, and how we can unlock its fossil secrets. The book uses simple text and full-color photographs throughout. With supporting facts, technical vocabulary, vivid maps and charts, and a variety of writing styles and text structures, Scholastic Discover More Readers are tailored to the new era of high expectations. The unique informational text reading levels have been developed and vetted by Scholastic reading experts. 学乐等级2，关于岩石和矿物的问题!整个世界是由岩石构成的!地球的岩石外壳形成数百万年，它充满了迷人的矿物质。你知道牙膏含有什...