Definição: A savanna biome is a woodland biome which has seasonal water availability and includes, across its entire spatial extent, trees spaced sufficiently far apart to allow an unbroken layer of grass, sedge (Cyperaceae) or rush (Juncaceae) communities to live.
Definição: Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.
Definição: An area that is inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.