c-undergoes the most change
Explanation:
Horizon B is the layer in a soil profile that has undergone the most change.
A section through a typical soil reveals many of the different layers.
The rock layers are divided into sections which are called horizons.
Horizon O is the organic matter
Horizon A is the top soil
Horizon B is the subsoil.
The subsoil of horizon B is the layer that undergoes the most change. It materials are constantly being leached away from this layer by chemical weathering. Some of the processes here accounts for it typical reddish brown color.
The rock layer here is rich in iron oxide and washed down minerals. It lacks significant amount of humus.
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Soil formation brainly.com/question/2473178
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