Thrombosis in which coronary artery is met most frequently in?

In humans,blood passes from the post caval to the diastolic right atrium of the heart due to:

The correct pathway of the impulse of heartbeat through the heart is ...........

$A$ heart murmur indicates a defective

Which of the following vessels carries the most oxygenated blood?

$SA$ node (Sinoatrial node) ke baare mein sahi kathan chuniye:
$I$. Located at the right upper corner of the right atrium.
$II$. Heart of heart.
$III$. It initiates the rhythmic contractile activity of the heart.
$IV$. It is called the pace-keeper of the heart.
$V$. It is called the pacemaker of the heart.
Which of the following options contains the correct statements?