Standard Science Primary 5 Systems

During gaseous exchange in the air sacs, which of the following enters the blood from the inhaled air?

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

Worked Solution

Step 1: Inhaled air is rich in oxygen. Step 2: In the air sacs, oxygen passes through the thin walls into the blood vessels. Step 3: Simultaneously, carbon dioxide moves from the blood into the air sacs.

Correct answer: Oxygen

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