Across
- 3. cycle the process by which oxygen released into the atmosphere by photosynthetic organisms
- 6. a large natural or artificial lake used as a source of water supply.
- 9. fixing they contain symbiotic bacteria called rhizobia within nodules in their root systems
- 10. person or thing eating something else.
- 11. the action or process of precipitating a substance from a solution.
- 12. total mass of organism in a given area or volume
- 16. process of turning from liquid to vapor.
- 17. process of oxidizing or being oxidized.
- 18. a leguminous plant.
- 20. using up a resource.
Down
- 1. colourless unstable toxic gas formed from oxygen.
- 2. process of burning something.
- 4. when a plant absorbs water in its roots
- 5. not derived from living organisms.
- 7. involving or requiring free oxygen.
- 8. permeation of a liquid into something by filtration.
- 13. rain made sufficiently by acid from the atmosphere.
- 14. the draining away of water from the surface of an area of land
- 15. organism that decomposes organic material.
- 19. fuel a natural fuel such as coal or gas.