Final answer:
Each suborder is divided into great groups, which are identified by specific factors, including soil horizons, moisture, and temperature. The A horizon represents the topsoil, whereas the B horizon is the subsoil.
Step-by-step explanation:
Each suborder is divided into great groups, determined by close similarities in kind, arrangement, and extent of soil horizon development, soil moisture and temperature regimes, base status, and is identified by the name of a suborder and by a prefix that indicates a property of the soil.
The soil profile includes layers such as the O horizon (organic material), the A horizon (topsoil), the B horizon (subsoil), and the C horizon (soil base). Soil formation is influenced by factors such as climate, organisms, relief, parent material, and time, leading to the development of distinct soil horizons with characteristic physical and chemical properties. The horizon considered as the topsoil is the A horizon, while the B horizon is considered as the subsoil.