Class 11 NEET Biology Body Fluids and Circulation

An ECG (Electrocardiogram) is a test that measures the electrical activities of the heart. Each wave in an ECG represents a certain part of the heart's electrical activity:
P wave : This wave occurs prior to the contraction of the atria (atrial contraction). It represents the depolarization of the atria.
QRS complex : This is a series of three graph deflections seen on a typical electrocardiogram. It corresponds to the depolarization of the ventricles, which initiates the ventricular contraction.
T wave : The T wave represents the repolarization (or recovery) of the ventricles.
By matching these descriptions with the options provided :
(A) P-wave - Depolarisation of atria (III)
(B) QRS complex - Depolarisation of ventricles (I)
(C) T wave - Repolarisation of ventricles (IV)
(D) End of T wave - End of systole (II)