Standard Science Primary 5 Systems

Which of the following correctly describes the change in the amount of nitrogen, oxygen, and carbon dioxide in the air as it is exhaled compared to when it was inhaled?

A Nitrogen increases, Oxygen decreases, Carbon Dioxide increases
B Nitrogen remains the same, Oxygen increases, Carbon Dioxide increases
C Nitrogen remains the same, Oxygen decreases, Carbon Dioxide increases
D Nitrogen decreases, Oxygen increases, Carbon Dioxide decreases
Show Worked Solution

Worked Solution

Step 1: Inhaled air contains about 78% nitrogen, 21% oxygen, and 0.03% carbon dioxide. Step 2: The body uses oxygen for respiration and produces carbon dioxide as waste. Step 3: Nitrogen is not used, so it remains unchanged. Oxygen decreases, and Carbon Dioxide increases. Step 4: Final Answer is Option B.

Correct answer: Nitrogen remains the same, Oxygen decreases, Carbon Dioxide increases

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