Question

Which describes the horizons in a soil profile?

Horizon A is mineral deficient.
Horizon O forms from organic material.
Horizon B undergoes the least amount of change.
Horizon C is most affected by the soil formation process.

Answer 1

Only "Horizon O forms from organic material" is correct.

Briefly:
- Horizon A is not mineral deficient — it's the mineral-rich topsoil mixed with organic matter.
- Horizon B does undergo change (accumulates clay, iron, and other materials from above).
- Horizon C is the least affected by soil-forming processes (partly weathered parent material).