Gear up to explore the wonders of mother Earth! Each 32-page book in this engaging 4-book set for reading levels 3ˆ4 features lively text, striking photographs, supporting graphics, highlighted vocabulary, a lab or problem-solving activity, sidebars, and graphs. Titles include The World of Rocks and Minerals, Investigating Plate Tectonics, Investigating Landforms, and People Who Predict.