To which of the following,bundle of His passes stimulus of contraction?

$A$: Endocardium provides a smooth lining for the inside of the heart and covers the valves of the heart.
$R$: Endocardium is continuous with the endothelial lining of the large blood vessels associated with the heart and the rest of the cardiovascular system.

Impulse originating from the sino-atrial node are transmitted to the

In which chamber of the heart is more blood present?

Foramen ovale

What is the membrane surrounding the heart called?