Soil and weathering

3. the size, shape, and position of the particles of soil
4. the top layer of soil that contains humus
6. the process by which rainwater dissolves and carries away minerals and nutrients in topsoil
8. the expansion of desert conditions in an area where the natural plant cover has been destroyed
11. the process of wearing something down by friction
12. the process in which transported sediment is laid down
14. horizon a soil layer with physical and chemical properties that differ from those of the soil layers above or below it
15. the process in which layers or sheets of rock gradually break off
17. the process by which natural forces break down rocks and soil
18. the makeup of rock or soil describing the minerals or elements present in it

1. weathering the breakdown of rock into smaller pieces of the same material without any change to its composition
2. weathering breakdown or decomposition of rock that takes place when minerals change through chemical processes
5. the ability to let water pass through
7. the decaying organic matter in soil
9. the process in which sediment is picked up and moved from one place to another
10. the amount of open space between an object
13. a chemical reaction in which an element combines with oxygen to form an oxide; iron oxide = rust
16. layer of rock beneath the soil