5. Larger surface area
Thin walls (facilitates easy
diffusion)
Good blood supply (oxygen in
& carbon dioxide out)
Must be moist (allows gases to
dissolve for easy transport)

6. Reagents:
-limewater, a clear, colorless solution turns
cloudy/milky when carbon dioxide is
present.
- Hydrogen carbonate indicator changes color
from red to yellow when carbon dioxide is
present.
 Inhaled air, less carbon dioxide 0.04%- no
change
 Exhaled air, more carbon dioxide 4%- change

7. Physical activity: e.g exercise, work
- during exercise, the rate of breathing increase and
becomes deep with intensity.---the more the
exercise you do, the deeper you breath.
How?:- rate & depth increases,heart pumps
blood faster in order to:
-supply oxygen & glucose to muscles
-remove carbon dioxide from lungs at a faster rate.

8.  Remove any accumulating lactic acid
 Reduce the oxygen debt

9.  Smoking, inhalation and exhalation of the
fumes of burning tobacco. Leaves of the
tobacco plant are smoked in various ways.
After a drying and curing process, they may
be rolled into cigars or shredded for insertion
into smoking pipes. Cigarettes, the most
popular method of smoking, consist of finely
shredded tobacco rolled in lightweight paper.

11.  Tobacco consists of the following
substances:
-Nicotine
-Tar
-Carbon monoxide
Effects of Nicotine
-damages or narrows blood vessels
-influence increased deposition of fat inside
the arteries causing artherosclerosis