Q.1
The percentage of oxygen in the air breathed in is .......
  • 0.03%
  • 1%
  • 21%
  • 79%
Q.2
The percentage of oxygen in the air breathed out is .......
  • 4%
  • 16%
  • 21%
  • 79%
Q.3
The percentage of carbon dioxide in inhaled air is .......
  • 0.03%
  • 4%
  • 21%
  • 79%
Q.4
The percentage of carbon dioxide in exhaled air is .......
  • 4%
  • 16%
  • 21%
  • 79%
Q.5
The percentage of which gas remains unchanged?
  • Carbon dioxide
  • Nitrogen
  • Oxygen
  • Water vapor
Q.6
Which is the correct order showing how oxygen enters the blood?
  • Alveoli, bronchioles, bronchi, trachea
  • Bronchi, bronchioles, trachea, alveoli
  • Trachea, alveoli, bronchi, bronchioles
  • Trachea, bronchi, bronchioles, alveoli
Q.7
Gas exchange takes place in the alveoli. Which is not true?
  • The alveoli have a moist surface
  • The alveoli have a small surface area
  • The alveoli have a very good blood supply
  • The alveoli have very thin permeable walls
Q.8
Oxygen passes from the alveoli into the blood. How is it transported?
  • By blood plasma
  • By dissolving in water
  • By red blood cells
  • By white blood cells
Q.9
Carbon dioxide passes into the alveoli from .......
  • arteries
  • blood plasma
  • platelets
  • white blood cells
Q.10
Air can enter and leave the lungs because .......
  • of pressure changes
  • the volume of the thorax (chest) remains the same
  • there is gas exchange
  • there is no pressure change
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