Standard Science Primary 5 Systems

What is the primary function of the air sacs (alveoli) in the lungs?

A To pump air to the heart
B To allow exchange of gases between air and blood
C To trap dust from the air
D To store oxygen for later use
Show Worked Solution

Worked Solution

Step 1: Air sacs have very thin walls and are surrounded by blood vessels. Step 2: This structure allows oxygen to enter the blood and carbon dioxide to leave it. Step 3: This process is called gaseous exchange.

Correct answer: To allow exchange of gases between air and blood

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