Chapter 7: Oxygen Cycle and Carbon Dioxide Cycle

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Across
  1. 6. needed by plants during photosynthesis
  2. 8. a component of cigarette that is addictive
  3. 10. sites for photosynthesis
  4. 15. opening on leaves that allow gaseous exchange
  5. 16. process of breathing out
Down
  1. 1. one-cell thick
  2. 2. food and air pass through here
  3. 3. moisten the inhaled air, traps bacteria and dust
  4. 4. our main respiratory organ
  5. 5. movement of gaseous molecule from a region of high concentration to a region of lower concentration
  6. 7. combines and transport oxygen
  7. 9. used to test for the presence of starch
  8. 11. a gas used during respiration
  9. 12. strengthen by C-shaped cartilage
  10. 13. process of breathing in
  11. 14. vibrate and produce sound