The heart sound 'dup' is produced when

(A)mitral valve is closed
(B)semi-lunar valves at the base of aorta get closed
(C)tricuspid valve is opened
(D)mitral valve is opened

The NCERT line that answers it

Verbatim line

The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves whereas the second heart sound (dub) is associated with the closure of the semilunar valves.

Chapter: Body Fluids and Circulation
Section: 15.3.2 Cardiac Cycle
Page: 7
Words matched: 31 of 31

The answer appears as a continuous sentence in NCERT. This is that sentence.

How this line gives the answer

0, emb=1.0, combined=1.0). Verified: high — The span explicitly states that the second heart sound (dub) is associated with the closure of the semilunar valves, which directly matches option B and distinguishes it from the other options.

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Every one traced to the exact sentence in NCERT that answers it, including 90% of the 2026 paper. Sit a mock on the real NEET 2027 computer interface and every mark you drop comes back with its line attached.

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Question text is reproduced from the published NEET 1994 paper for study and commentary. NCERT text is quoted, not redistributed; textbooks remain at ncert.nic.in. Our mapping method, including its measured error rates, is published at /methodology.