soil and weathering

3. layer of rock beneath the soil
5. the size, shape, and position of the particles of soil
6. the amount of open space between an object
10. the ability to let water pass through
12. the process by which rainwater dissolves and carries away minerals and nutrients in topsoil
13. the decaying organic matter in soil
15. weathering breakdown or decomposition of rock that takes place when minerals change through chemical processes
16. the process in which layers or sheets of rock gradually break off
17. the process in which transported sediment is laid down

1. the process by which natural forces break down rocks and soil
2. the makeup of rock or soil describing the minerals or elements present in it
4. weathering the breakdown of rock into smaller pieces of the same material without any change to its composition
7. horizon a soil layer with physical and chemical properties that differ from those of the soil layers above or below it
8. the expansion of desert conditions in an area where the natural plant cover has been destroyed
9. a chemical reaction in which an element combines with oxygen to form an oxide; iron oxide = rust
11. the top layer of soil that contains humus
14. the process of wearing something down by friction
18. the process in which sediment is picked up and moved from one place to another