Standard Science Primary 5 Systems

How do the numerous tiny air sacs in our lungs help us breathe more efficiently?

A They increase the surface area for faster gas exchange.
B They filter out dust from the air.
C They help the heart pump blood faster.
D They produce mucus to trap bacteria.
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Worked Solution

Step 1: Air sacs (alveoli) are where oxygen enters the blood and CO2 leaves it. Step 2: Having millions of tiny sacs provides a massive total surface area. Step 3: More surface area allows more gas molecules to cross at the same time.

Correct answer: They increase the surface area for faster gas exchange.

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