science extra credit!

2. a wind-formed deposit made of fine particles of clay and silt
5. rotation, the planting of different crops in a field each year to maintain the soil's fertility
6. film, a type of fossil consisting of an extremely thin coating of carbon on rock
8. the process by which wind removes surface
9. a measure of how well soil supports plant growth
12. preserved remains or traces of an organism that lived in the past
13. water that fills the crack and spaces in underground soil and rock layers
14. a loose collection of ice and dust that orbits the sun typically in a long, narrow orbit
16. glacier , a glacier that covers much of a continent or large island
19. the attractive force between objects; the force that moves objects downhill
20. a flat model of all or part of Earth's surface as seen from above

1. a igneous rock layer formed when lava flows onto earth's surface and hardens
2. the distance in degrees north or south of the equator
3. a sphere that represents Earth's entire surface
4. any large mass of ice that moves slowly over land
7. the time it takes for half of the atoms of a radioactive element to decay
10. plain, the flat wide area of land along a river
11. the process that break down rock and other substances
15. the process of wearing down and carrying away rocks
17. plowing, plowing fields along the curves of a slope to prevent soil loss
18. a break in earth's crust along which rocks move