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: A landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit and a local relief of more than 300m.
Definição: An area of land of low topographic relief that historically supported grasses and herbs, with few trees, and having generally a mesic (moderate or temperate) climate. Dominated by tall grasses (contrast steppe).
