respiratory system

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Across
  1. 3. It is naturally present in air and is absorbed by plants in photosynthesis.
  2. 5. a pair of organs in the rib-cage
  3. 6. he large air passages that lead from the trachea to the lungs.
Down
  1. 1. The airway that leads from the larynx to the bronchi and it is also called a windpipe
  2. 2. it is an organ forming an air passage to the lungs and it is also called the voice box
  3. 4. It plays a major role in breathing, as its contraction increases the volume of the thorax and so inflates the lungs.