What are the three steps of soil horizons?

The A horizon, the uppermost layer in the soil profile, often is called the surface soil. It is the part of the soil in which life is most abundant in such forms as plant roots, bacteria, fungi, and small animals. It is the part in which organic matter is most abundant.

The B horizon lies immediately beneath the A horizon and often is called the subsoil. Lying between the A and C horizons, it utilizes the properties of both. Living organisms are fewer than in the A horizon but more abundant than in the C horizon.

THE C horizon is the deepest of the three major horizons. It consists of the loose and partly decayed rock beneath the A and B horizons. The rock material in the C horizon is of the same kind which now forms the bulk of the soil above it.