What is the study of the circulatory system called?

Compare the statements $A$ and $B$.
$Statement A$: Blood sugar level falls rapidly after hepatectomy.
$Statement B$: The glycogen of the liver is the principle source of blood sugar.
Select the correct description:

The organ that acts as a filter for blood is:

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 of the following figures correctly represents the path of a closed circulatory system?

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