Standard Science Primary 5 Systems

Which of the following describes the difference between the air we inhale and the air we exhale?

A Exhaled air is cooler than inhaled air.
B Exhaled air has more oxygen and less carbon dioxide.
C Inhaled air has no carbon dioxide at all.
D Exhaled air has less oxygen and more carbon dioxide.
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Worked Solution

Step 1: When we inhale, our body takes in oxygen from the air for respiration. Step 2: Respiration produces carbon dioxide as a waste gas, which we exhale. Step 3: Therefore, exhaled air has less oxygen (because it was used) and more carbon dioxide (because it was produced) compared to inhaled air.

Correct answer: Exhaled air has less oxygen and more carbon dioxide.

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