Geography

4. An official agreement intended to resolve conflict
8. A built environment refers to the human-made surroundings that provide the setting for human activity
10. A biological community of interacting organisms and their physical environment
13. The action of conserving something, in particular
14. The regions of the surface and atmosphere
15. Seriously at risk of extinction.

1. No longer in existence
2. All the waters on the earth's surface
3. The natural home or environment of an animal, plant, or other organism
5. A diagrammatic representation of an area of land or sea showing physical features, cities, roads
6. The process by which fertile land becomes desert
7. gases surrounding the earth or another planet
9. The crust and upper mantle of the earth.
11. of or relating to facility in perceiving relations
12. A line on a map joining points of equal height above or below sea level