Although rock is the basic component of , the composition and texture of soil and its and resistance to erosion are greatly influenced by plant roots and debris, , fungi, , insects, rodents, and other organisms. The upper-most layer of the crust is covered by soil. The ingredients in soils can vary from place to place and around the Earth. soils have many such as , particle size, , fertility and ability to hold moisture. Depending upon the combination of properties, soils have great variability in their ability to support structures and plant growth. Forces deep inside Earth and at the surface produce a slow cycle that builds, destroys, and changes the rocks in the crust. movements start the cycle by helping to form , the source of igneous rocks. Plate movements also cause faulting, folding and other motions of the crust that help to form and rock. form as hot magma cools inside the crust, or as hardens on the surface. When these liquids cool to a solid state, they form . When elements and compounds that are dissolved in water leave a , crystallization of minerals occurs. is a mixture of: rock particles, minerals, decayed organic matter, water and air. Soil forms as rock is broken down by weathering and mixes with other materials on the surface. fill in the blanks now!