Standard Science Primary 5 Systems

Siti measured her breathing rate while resting and after running for ten minutes. Which statement best explains why her breathing rate increased after running?

A To allow her heart to beat faster and pump blood.
B To produce more energy for her leg muscles to move.
C To take in more oxygen and remove more carbon dioxide.
D To cool down her body temperature after exercise.
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Worked Solution

Step 1: During exercise, muscles need more energy. Step [2-9]: Increased respiration requires more oxygen and produces more carbon dioxide as waste. Step [2-9]: The respiratory system speeds up to exchange these gases faster.

Correct answer: To take in more oxygen and remove more carbon dioxide.

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