Respiration

Name: ______________________   Date: ____________

Use the clues to fill in the crossword.

Across

  1. 2. An oxide containing two atoms of oxygen in the molecule (7)
  2. 4. The power to do work or make things move (6)
  3. 8. Living or active in the absence of free oxygen (9)
  4. 11. Gas in the air that we need to breathe (6)
  5. 12. Red liquid pumped around the body by the heart (5)
  6. 13. Either of two saclike respiratory organs in the chest of vertebrates (plural) (5)

Down

  1. 1. A mechanical device in a camera that controls size of aperture of the lens (9)
  2. 3. Depending on free oxygen or air (7)
  3. 5. A monosaccharide sugar that has several forms (7)
  4. 6. Clear liquid we drink that falls as rain (5)
  5. 7. An abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous ___ (6)
  6. 9. Support resembling the rib of an animal (plural) (4)
  7. 10. Tiniest unit of living things (plural) (5)