Natural environments

7. Opening in the Earth's crust through which molten lava, ash, and gases are expelled
8. Large mass of ice that moves slowly down a slope or valley, shaping the surrounding landscape
9. Large expanse of flat or rolling grassland, typically found in temperate regions
10. Ring-shaped coral reef or series of islets surrounding a central lagoon
11. Vast, treeless Arctic or Alpine region characterized by low temperatures and a short growing season
13. Arid region with minimal vegetation, characterized by sand dunes, rocky landscapes, or vast expanses of barren land
14. Underwater ecosystem formed by colonies of coral polyps, supporting a diverse array of marine life
15. Grassy plain characterized by scattered trees and supporting a range of wildlife

1. A cascade of water that flows from a height, often creating a picturesque scene
2. Natural flowing watercourse, often originating from a source and emptying into a larger body of water
3. Sandy or pebbly shore by the ocean or a lake, with waves and coastal features
4. Dense area of trees, plants, and wildlife, often with a variety of ecosystems
5. Large landform that rises steeply above its surroundings, often with rocky terrain and snow-capped peaks
6. Deep and narrow valley with steep sides, usually formed by erosion from a river or other natural forces
10. Natural underground hollow or passage, often with unique geological formations
12. Area where water covers the soil, such as marshes, swamps, or bogs, supporting diverse plant and animal life