The b horizon is also called the subsoil unaltered parent material partially altered parent material topsoil

subsoil

Explanation:

THe B horizon is what we call the layer of soild that is directly after the A-horizon, or normal soil when we dig up, the B horizon is also called the sub soil, which comes from the root sub- which means directly below, in its name expresses the reality of its meaning whihc is the soil that is directly below the surface soil.

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