An electrocardiograph technician knows one small block on the ECG paper represents 1/25
of a second. How many seconds do 150 small blocks represent?

The ECG paper speed is ordinarily 25 mm/sec. As a result, each 1 mm (small) horizontal box corresponds to 0.04 second (40 ms), with heavier lines forming larger boxes that include five small boxes and hence represent 0.20 sec (200 ms) intervals.

Explanation:

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what effect does exercise have on the nervous system?

the answer is c.