| A | B |
|---|
| horizons | layers of soil |
| soil profile | all the layers of soil |
| mature soil profile | topsoil, subsoil, parent material above bedrock |
| humus | decayed organic material in soil |
| most animals live in this horizon | topsoil |
| sand, silt, clay | come from weathered bedrock |
| clay | soil type with small, flat particles |
| sand | soil type with large, irregularly shaped particles |
| permeable | soil with spaces that allow water to flow through |
| soil type that is very permeable | sand |
| soil type that is not very permeable | clay |
| If soil quality changes | the ecosystem will change |
