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AymanAbdelhDY AymanAbdelhDY
wrote...
Posts: 444
Rep: 0 0
6 years ago
At sea level, what percentage of the air we breathe is oxygen?
  a. 21
  b. 30
  c. 50
  d. 79
  e. 100

Question 2

The major site of gas exchange in the lungs is the ____.
  a. bronchi
  b. bronchioles
  c. larynx
  d. alveoli
  e. respiratory bronchioles
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Replies
wrote...
6 years ago
Answer to q. 1

ANSWER: a

Answer to q. 2

ANSWER: d
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