Across
- 4. Swellings on roots containing bacteria necessary for nitrogen-fixing
- 5. Rain containing high amounts of chemical pollutants
- 6. nitrogen nitrogen gas which is not chemically combined with any other substances
- 7. Process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem
- 8. Unicellular microscopic organisms in plants/soil used in the process of nitrogen fixation
- 12. Converting atmospheric nitrogen into nitrogen compounds, useable forms for plants
- 15. Organisms that break down wastes and dead organisms and return raw materials to the environment
- 16. Gaseous element that forms about 78% of the atmosphere and is in animal and plant matter
- 17. Manure, or any organic substance, or a chemical that makes soil richer in plant foods when it is spread over or put into soil
- 18. Process when plants absorb nitrogen compounds from the soil via theis roots
- 19. Two or more elements chemically combined
- 20. Complex organic compounds combined to form proteins that make up living matter
Down
- 1. Layers of gases that surround the earth
- 2. A pungent gas compounded of nitrogen and hydrogen (NH3)
- 3. Process by which bacteria convert nitrates in the soil into nitrogen gas
- 9. nitrogen nitrogen that's chemically combined with hydrogen, oxygen or carbon
- 10. Substance that makes up the living materials/parts of cells
- 11. Any plant of the pea or bean family which aborbs nitrogen from the air and, by means of bacteria, converts it to a useble form
- 12. Process by which certain bacteria convert ammonium to nitrates
- 13. Coal, oil, natural gas, and other fuels that are ancient remains of plants and animals
- 14. Process when bacteria convert the organic nitrogen within plant and animal wastes back into ammonium compounds