Earth Science 6.1

21. the radiation from the sun that causes chemical reactions, generates electricity, and produces heat.

20. organic matter that contains stored energy and is useful to produce fuel.

7. the planting of alternating bands of crops and cover vegetation in a planned rotation that are of equal widths

11. a source of energy formed from the buried remains of dead plants and animals.

4. any substance, organism, or energy form found in nature that can be used by living things

12. a mixture of methane and other gases formed from decomposed marine organisms

3. the energy collected from heat trapped in the earth’s crust

10. a solid fossil fuel formed from decomposed plant remains

16. a location where rocks are removed from the ground.

6. a resource that's constantly available or can be replaced in a short period of time through natural processes

15. a naturally occurring mineral from which a useful metal or mineral is recovered. 

9. a resource that cannot be replaced once it is used or can only be replaced over an extremely long period of time. 

8. the construction of step like ridges that are built into the slope of the land

1. the plowing of furrows around a hill perpendicular to its slope to reduce erosion

5. the energy that comes from changes in the nuclei of atoms of radioactive elements

2. the successive planting of different crops on land to prevent erosion and to improve fertility

19. a ditch in farmland

18. the fast growing vegetation planted on bare farmland to prevent erosion. 

13. a substance made of partially decayed plant matter.

17. the making of new deserts by degrading land that used to be healthy and productive 

14. a liquid fossil fuel formed from microscopic plants, animals, and marine organisms.