Across

1. A clump or tuft, as of growing grass.

3. Either the northern or southern half of the earth as divided by the equator or the eastern or western half as divided by a meridian.

5. Extremely cold; frigid.

6. One of the principal land masses of the earth, usually regarded as including Africa, Antarctica, Asia, Australia, Europe, North America, and South America.

9. Permanently frozen subsoil, occurring throughout the Polar Regions and locally in perennially frigid areas.

10. A fungus that grows symbiotically with algae, resulting in a composite organism that characteristically forms a crustlike or branching growth on rocks or tree trunks.

11. Living or growing on mountains above the timberline.

12. Relating to, connected with, or located near the North Pole or South Pole .

13. An alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relationship to its environment.

14. Something that provides cover or protection, as from the weather.

Down

2. Someone who works to protect the environment from destruction or pollution.

4. An area of land.

7. Marked by unforeseen hazards; dangerous or deceptive.

8. An area or a region distinguished from adjacent parts by a distinctive feature or characteristic.

15. A treeless area between the icecap and the tree line of Arctic regions, having a permanently frozen subsoil and supporting low-growing vegetation such as lichens, mosses, and stunted shrubs.