Standard Science Primary 5 Systems

Compare the air we inhale with the air we exhale. Which statement is correct?

A Exhaled air contains more water vapour than inhaled air.
B Exhaled air contains only carbon dioxide.
C Exhaled air contains more oxygen than inhaled air.
D Inhaled air contains no nitrogen.
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Worked Solution

Step 1: Recall air composition changes during respiration. Step 2: Oxygen decreases, carbon dioxide increases, and water vapour increases due to moisture in the lungs. Step 3: Nitrogen levels remain the same.

Correct answer: Exhaled air contains more water vapour than inhaled air.

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