Across
- 5. The movement of oxygen from the atmosphere to living organisms and back to the atmosphere
- 7. A type of symbiosis that benefits both organisms
- 8. The movement from the atmosphere into living organisms, then into the
- 9. The water in the clouds returns to the earth by falling as precipitation
- 10. Plants absorb the nitrogen compounds from the soil and use them to make protein
Down
- 1. The process by which a plant uses energy from the sun to turn carbon dioxide and water into the sugar glucose
- 2. Water leaves the earth through evaporation and enters the atmosphere as a gas called water vapor. Most of the time it takes place in from the surface of large bodies of water
- 3. Water vapor cools and becomes liquid again in a process called
- 4. Animal waste and the dead bodies of organisms are broken down by soil bacteria and become useful nitrogen compounds once again
- 6. Other soil bacteria convert the nitrogen compounds back into nitrogen gas