Each concept here is mapped to its prerequisites — the ideas you'd need first to understand it — all the way down to four foundations: Space, Time, Energy, Pattern. Click any prerequisite to drill down, or scroll for the chain graph.
Subsoil is the layer of earth beneath the topsoil, where organisms interact with the planet's physical properties, influencing the environment and being influenced by it.
External reference — all senses of the word “subsoil” on Wiktionary. This atlas concept maps to only the slice of meaning relevant to the prerequisite graph.