* A horizon (topsoil): This is the uppermost layer, rich in organic matter from decayed plant and animal material. It's typically darker in color and is where most biological activity takes place.

* B horizon (subsoil): This layer lies beneath the topsoil and is characterized by mineral accumulation. It's often denser and less fertile than the A horizon, and may have a different color due to the presence of clay, iron oxides, or other minerals.

* C horizon (parent material): This is the deepest layer, composed of weathered bedrock or other parent material from which the soil developed. It's usually less affected by biological activity and shows fewer signs of development compared to the upper layers.

These three horizons are not always distinct, and their characteristics can vary depending on the soil type, climate, and other factors.