4 POINTS ON SOIL

 1. Soil is an ecosystem comprising weathered rock, organic matter, animals, plants and micro organisms.

2.  Various horizontal layers are discernible, including, humus, the topmost layer of rotting organic matter

3. Top soil, which is rich in minerals and humus; subsoil, which has less humus but plentiful minerals;

4. A layer of rock fragments with little organic content; and bedrock, the underlying solid rock