Answer 1

	P-wave	T-wave
1	In an electrocardiogram (ECG), the P-wave indicates the activation of the SA node.	In an electrocardiogram (ECG), the T-wave represents ventricular relaxation.
2	During this phase, the impulse of contraction is generated by the SA node, causing atrial depolarisation.	During this phase, the ventricles relax and return to their normal state.
3	It is of atrial origin.	It is of ventricular origin.