Respiration

Name: ______________________   Date: ____________

Use the clues to fill in the crossword.

Across

  1. 4. Support resembling the rib of an animal (plural) (4)
  2. 6. A mechanical device in a camera that controls size of aperture of the lens (9)
  3. 7. A ___ in which ___ circulates (plural) (12)
  4. 8. Either of the two main branches of the trachea (8)
  5. 9. One of the tubules forming the respiratory system of most insects and many arachnids (7)
  6. 11. The opening through which food is taken in and vocalizations emerge (5)
  7. 12. The organ of smell and entrance to the respiratory tract (4)

Down

  1. 1. The power to do work or make things move (6)
  2. 2. A blood vessel that carries blood from the capillaries toward the heart (plural) (5)
  3. 3. Any of the minute blood vessels connecting arterioles with venules (plural) (11)
  4. 5. Any of the smallest ___ ducts (plural) (11)
  5. 10. Either of two saclike respiratory organs in the chest of vertebrates (4)