Across
- 3. acid HNO2
- 4. lead a colorless, poisonous, oily liquid
- 10. small particles of dust released into the atmosphere by many natural processes and human activities.
- 12. a form of oxygen that has three oxygen atoms in each molecule instead of the usual two.
- 13. poisonous
- 15. a form of oxygen that has three oxygen atoms in each molecule instead of two.
- 16. The chemical element of atomic number 16; a yellow combustible nonmetal.
- 17. inhalation and exhalation of air.
Down
- 1. The natural home or Enviroment of an animal,plant,or other organism.
- 2. any organism that damages valuable crops.
- 5. compounds composed of only carbon and hydrogen.
- 6. process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high energy carbohydrates.
- 7. a long, thin fibrous silicate mineral with insulting properties, which can cause cancer when inhaled.
- 8. a colorless, transparent, odorless liquid that forms the seas,lakes,rivers, and rain and is the basis of the fluids of living organisms.
- 9. material material contaminated by residue from the generation of nuclear energy.
- 11. The invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen.
- 14. the upper layer of earth on which plants grow.