The number of action potentials generated by sino-atrial node (SAN) in a healthy human is _____ per minute.

(A)28 - 30
(B)70 – 75
(C)100 - 110
(D)120 - 140

The NCERT line that answers it

Verbatim line

The SAN can generate the maximum number of action potentials, i.e., $70-75 \text{ min}^{-1}$ , and is responsible for initiating and maintaining the rhythmic contractile activity of the heart.

Chapter: Body Fluids and Circulation
Section: 15.3.1 Human Circulatory System

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

How this line gives the answer

6667, emb=1.0, combined=0.8667). Verified: high — The span explicitly states that the SAN generates 70-75 action potentials per minute, which directly matches the correct option B and distinguishes it from the other options.

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