The components and importance of air

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Across
  1. 3. Plants use carbon dioxide in a process to make food known as p________. (page 124)
  2. 5. The atmosphere helps to maintain the t_______ of Earth. (page 126)
  3. 9. We _______ in oxygen. (page 124)
  4. 11. Microorganisms such as b_______ can make us sick. (page 125)
  5. 13. What is the largest component of air? (page 124)
  6. 16. There are other things in the air such as m_______. (page 125)
  7. 19. The layer of air surrounding Earth is called... (page 123)
  8. 20. Noble gases have n____ in them. (page 125)
  9. 21. Without air, we cannot hear any ______. (page 126)
  10. 22. Carbon dioxide is a useful gas for p_____. (page 124)
  11. 24. Noble gases have h____ in them. (page 125)
Down
  1. 1. W____ v____ is also present in the air. 2 words (page 125)
  2. 2. Air is a m______ of different gases. (page 123)
  3. 4. A toy that needs air to work. b____ b___. 2 words (page 127)
  4. 6. Nitrogen is used to make fertilizers, e_________ and other substances. (page 124)
  5. 7. Our body needs oxygen to produce e_____ from the foot we eat. (page 124)
  6. 8. B_______ filled with helium float upwards. (page 125)
  7. 10. This is in the air. D___. (page 125)
  8. 11. Oxygen is needed for b______. (page 124)
  9. 12. Argon is used to fill l____ b____. 2 words (page 125)
  10. 14. Oxygen is needed for r______. (page 124)
  11. 15. Nitrogen is U_________. (page 124)
  12. 17. Air is mixture of nitrogen, ______, carbon dioxide and noble gases. (page 123)
  13. 18. Without oxygen, living things cannot s______. (page 124)
  14. 19. Noble gases have a____ in them. (page 125)
  15. 23. Sound needs air to t_____. (page 126)