science

5. the chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle.
7. a colorless, odorless gas produced by burning carbon and organic compounds and by respiration.
10. the process of burning something.
13. a body of permeable rock which can contain or transmit groundwater.
14. a process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances.
16. a simple sugar which is an important energy source in living organisms and is a component of many carbohydrates.
17. the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
18. the chemical element of atomic number 7, a colorless, odorless unreactive gas that forms about 78 percent of the earth's atmosphere.

1. a natural fuel such as coal or gas, formed in the geological past from the remains of living organisms.
2. the process of turning from liquid into vapor.
3. Algal blooms are dense layers of tiny green plants that occur on the surface of lakes and other bodies of water
4. a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some that can cause disease.
6. the loss or removal of nitrogen or nitrogen compounds
8. a prolonged period of abnormally low rainfall, leading to a shortage of water
9. water which collects as droplets on a cold surface when humid air is in contact with it.
11. the action or process of precipitating a substance from a solution.
12. the state or process of rotting; decay.
14. the draining away of water (or substances carried in it) from the surface of an area of land, a building or structure, etc.
15. the envelope of gases surrounding the earth or another planet.