The three layers of a normal soil profile are ?

• A. Topsoil, subsoil, and bedrock
• B. Root zone, tap soil, bedrock
• C. Sand, silt, clay
• D. Topsoil, subsoil, and root zone

Answer: (A)

Understanding a soil profile means looking at how soil forms in layers from the surface downward. The surface layer, topsoil, holds most of the organic matter and nutrients that plants need. Beneath it is the subsoil, which contains minerals that have leached down from above and typically has less organic material. At the bottom sits bedrock, the solid rock that weathering slowly breaks down to form soil over time. So, the three main layers in a typical soil profile are topsoil, subsoil, and bedrock. The root zone describes where roots grow rather than a distinct layer, and sand, silt, and clay refer to particle sizes, not layers of the profile.