Did you know that there are horizons in the soil? They're named O, A, B, and C. O is the top horizon. It's about an inch thick made up of dead stuff that breaks down and keeps the soil "O"-so healthy. The A horizon is topsoil that's alive with roots, tiny microstuff like bacteria and fungi, and all kinds of critters like me. The A horizon is "A-OK" with me. Number three is horizon B. Plants and animals have a tough time getting through B. Why? "B"-cause it's very hard. See horizon C? You see, horizon C has less living stuff in it than O, A, and B. C is parent material that's made up of the rock and soil that formed the three layers above it.