Solved UPSC CDS/OTA Question
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Q · Respiratory System Medium · 45s
Which gas regulates breathing rate under normal conditions?
TopicRespiratory System
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
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Your breathing rate is primarily controlled by CO₂ levels in the blood, not oxygen (O₂).
When CO₂ levels increase, it causes the blood to become more acidic (lower pH), which is detected by chemoreceptors in the brain and blood vessels.
This triggers the medulla oblongata (in the brainstem) to increase the breathing rate to expel more CO₂ and restore pH balance.
Final Answer: Option B - CO₂