Natural environments

4. Dense area of trees, plants, and wildlife, often with a variety of ecosystems
6. Natural underground hollow or passage, often with unique geological formations
9. Vast, treeless Arctic or Alpine region characterized by low temperatures and a short growing season
10. Large expanse of flat or rolling grassland, typically found in temperate regions
13. Opening in the Earth's crust through which molten lava, ash, and gases are expelled
14. Atoll Ring-shaped coral reef or series of islets surrounding a central lagoon
15. Grassy plain characterized by scattered trees and supporting a range of wildlife
16. Reef Underwater ecosystem formed by colonies of coral polyps, supporting a diverse array of marine life

1. Arid region with minimal vegetation, characterized by sand dunes, rocky landscapes, or vast expanses of barren land
2. Large landform that rises steeply above its surroundings, often with rocky terrain and snow-capped peaks
3. Natural flowing watercourse, often originating from a source and emptying into a larger body of water
5. A cascade of water that flows from a height, often creating a picturesque scene
7. Deep and narrow valley with steep sides, usually formed by erosion from a river or other natural forces
8. Area where water covers the soil, such as marshes, swamps, or bogs, supporting diverse plant and animal life
11. Large mass of ice that moves slowly down a slope or valley, shaping the surrounding landscape
12. Sandy or pebbly shore by the ocean or a lake, with waves and coastal features