Solved UPSC CDS/OTA Question
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Q · Excretory Systemmedium · 45s
Which substance is secreted into the proximal tubule for excretion?
TopicExcretory System
Question Typemultiple choice
Difficultymedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
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The proximal tubule secretes hydrogen ions into the filtrate through Na⁺/H⁺ exchangers and H⁺-ATPase, contributing to acid–base balance by allowing HCO₃⁻ reabsorption.
Final Answer: Option B - H⁺ ions