\n– **Oxisols (A):** These are highly weathered soils, typically found in tropical and subtropical regions. They are characterized by subsurface horizons dominated by residual accumulations of iron and aluminum oxides and lack of weatherable minerals. They are indeed very old and highly weathered (matches 3).
\n– **Vertisols (B):** These are clay-rich soils that shrink and swell significantly upon drying and wetting, respectively. This shrink-swell action creates deep cracks. They are often rich in montmorillonite clay and can be highly basic (matches 4).
\n– **Histosols (C):** These are organic soils formed in wetlands, composed mainly of peat or muck. They contain a large amount of organic matter, usually more than 20% (matches 1).
\n– **Entisols (D):** These are young soils that have little or no morphological development of pedogenic horizons. They lack distinct layers characteristic of more developed soils (matches 2).
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