This book introduces readers to what makes up soil, from humus and plants and animals to water and air. Learn how weathering, erosion, parent material, decay, bacteria, organic matter, climate, and time contribute to soil formation. A geology-themed project provides the opportunity for hands-on experience. Other features include a table of contents, fun facts, infographics, sidebars, and an index. Aligned to Common Core Standards and correlated to state standards. Checkerboard Library is an imprint of Abdo Publishing, a division of ABDO.