Hypokalaemia means

The breakdown product of haemoglobin is

All of the following are vasoconstrictor agents except:

Statement-$I$ :- The body has the ability to alter the stroke volume as well as heart rate and thereby the cardiac output.
Statement-$II$ :- During each cardiac cycle two prominent sounds are produced which can not be easily heard through a stethoscope.

Which one of the following is a matching pair of a certain body feature and its value/count in a normal human adult?

Which of the following cardiac effects can be observed if the potassium concentration is increased two to three times the normal value?