Which component of the ekg causes the heart to contract?
a. qrs complex
b. t wave
c. p wave
d. av node?

The right answer is QRS complex.

The electrocardiogram records a succession of sequences of the electrical activity of the heart, represented by waves named P, QRS and T:

*The P wave is that of the atria at the moment of their contraction,

*The QRS complex corresponds to the contraction of the ventricles,

*The T wave reflects the repolarization (return to the rest phase) of the ventricles.

this is true my friend.