$ECG$ helps in the diagnosis of the following abnormalities in conducting pathways $EXCEPT$ . . . . . . .

The given diagram represents a normal $ECG$ record of a human heart. Select the $CORRECT$ match from the options given below:

What is the normal pulse pressure?

Given below are two statements.
Statement $I$ - Graphical recording of electrical variations detected at the surface of body during their propagation through the wall of heart is electrocardiograph.
Statement $II$ - The instrument used for the graphical recording of electrical variations detected at the surface of body during their propagation through wall of heart is electrocardiogram.
In the light of above statements,select the correct option given below:

In $\text{ECG}$,the $\text{QRS}$ complex represents:

What is represented by the $P$-wave in an $ECG$?