Soil is a mixture of weathered rock and decayed organic matter that forms over long periods of time. Soil formation involves the weathering of bedrock, growth of mosses and vegetation, and decay of organisms which adds humus and nutrients to the soil layers. Soil is made up of distinct layers called horizons, with the topsoil near the surface containing the most plant roots and organic material. The type of soil that forms depends on various environmental factors like climate, vegetation, parent material, topography, and time.