| 1. The thorax contains two major organs, the lungs and
the
. |
| 2. When we breathe in the ribs
and the diaphragm
. |
| 3. When we exercise we breathe faster and
.than when we are resting. |
| 4. The trachea has rings of
.around it to stop it from collapsing. |
| 5. The trachea divides into two
.
to take air in and out of each lung. |
| 6. The lungs are full of microscopic air sacs called
.
and microscopic blood vessels called
. |
| 7. The air that we breathe in contains more
.
than the air that we breathe out. |
| 8. The air that we breathe out contains more
.
and
.
than the air that we breathe in. |
| 9. The gases
.and carbon dioxide are transported around the body in the
. |
| 10. The gas carbon dioxide is produced all over our bodies
by the process called
. |
| 11. To prevent dust from entering the lungs the
.
has hairs and mucus to trap the large dust particles. |
| 12. The trachea is also covered in mucus which traps fine
dust particles. This mucus is swept up to the mouth by microscopic hairs
called
. |
| 13. So that the food and drink does not pass into the
trachea when we swallow, the entrance to the trachea is protected by
the
. |
| 14. When a person smokes a cigarette he breathes in
chemicals such as
.
which can damage the lungs. |
| 15. The exhaust gases of motor cars contain
.which
combines with the
to prevent it from carrying oxygen. |
