Topic 8 Review - 6th Grade

2. Farming that only provides the basic needs of a family.
3. Any significant change in the measures of climate lasting for an extended period of time.
6. A resource formed in the Earth by plant and animal remains.
8. Growing large quantities of crops or livestock to sell for a profit.
10. The planting and cultivating of new trees in an effort to restore a forest where the trees have been cut down or destroyed.
11. Rain that contains harmful amounts of poisons due to pollution; precipitation carrying large amounts of dissolved acids.
13. A boundary where a higher, upland area drops to the lower land of a plain.
14. A sudden and extreme event in nature that usually results in serious damage and loss of life.
16. The process of collecting and moving water for use in agriculture.
17. The process by which an area turns into a desert.
18. The loss or destruction of forests, mainly for logging or farming.

1. A resource that cannot be replaced.
4. Materials or substances such as minerals, forests, water, and fertile land that occur in nature
5. The idea that a country works to create conditions where all natural resources for meeting the needs of society are available.
7. Haze caused by chemical fumes from automobile exhausts and other pollution sources.
9. A resource that can be replenished in a relatively short period of time.
12. A layer around the Earth’s atmosphere that blocks out many of the most harmful rays from the sun.
15. A process that makes salt water safe to drink; the removal of salt from seawater to make it usable for drinking and farming.