Soil is formed through the weathering of rock and organic processes. It is composed of weathered rock particles, water, air, and organic matter. The type of soil that forms depends on the underlying rock type, climate, landforms, plant life, and soil organisms. Soil develops in horizontal layers called horizons, with the A horizon at the top containing more organic matter and the C horizon at the bottom containing larger rock particles. Climate, landforms, and the activities of organisms like plants, microbes, earthworms, and animals influence the characteristics of different soils.