Standard Science Primary 5 Systems

Which of the following describes the change in air composition after we breathe it out?

A Water vapour decreases
B Carbon dioxide increases
C Nitrogen increases
D Oxygen increases
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Worked Solution

Step 1: Our body uses oxygen for respiration. Step 2: Respiration produces carbon dioxide as a waste product. Step 3: Exhaled air contains more carbon dioxide and less oxygen than inhaled air.

Correct answer: Carbon dioxide increases

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