Answer:
undergoes the most change
Explanation:
The soils are divided into several layer, or rather horizons. The horizon B is the third layer from the top, with the horizon O and horizon A being above. This layer of the soil is deeper than the two on top of it, and it also has more compact structure. Despite this, the horizon B is the layer that undergoes the most changes. The reason for this is that this layer is the one in which the water and the organic matter are washed away. That constantly contributes to changes in its composition and structure. Also, the roots of the trees penetrate into it, and by releasing gases as byproducts they do to contribute to changes in this layer. Over time, the horizon B is actually becoming more and more fertile, as more and more material in its weathered, and it gets more and more, water, gases, and organic matter.
