Solved UPSC CDS/OTA Question
A solved UPSC CDS/OTA PYQ — decoded step-by-step.
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Q · Circulatory SystemMedium · 45s
The heart sounds ‘lub’ and ‘dub’ are due to:
TopicCirculatory System
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
‘Lub’ is the closing of AV valves, ‘Dub’ is the closing of semilunar valves.
Final Answer: Option B — Closing of valves