Standard Science Primary 5 Systems

Which of the following increases when a person exercises to ensure muscles get enough oxygen?

A Only the heart rate
B Neither the breathing rate nor heart rate
C Only the breathing rate
D Both the breathing rate and heart rate
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Worked Solution

Step 1: Muscles need more energy/oxygen during exercise. Step 2: The lungs (respiratory) must take in more oxygen (higher breathing rate). Step 3: The heart (circulatory) must pump that oxygenated blood faster (higher heart rate).

Correct answer: Both the breathing rate and heart rate

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