Which structure is formed from the bundle of His?

Match the items given in Column-$I$ with those in Column-$II$ and select the correct option given below:

Column-$I$	Column-$II$
$(a)$ Tricuspid valve	$(i)$ Between left atrium and left ventricle
$(b)$ Bicuspid valve	$(ii)$ Between right ventricle and pulmonary artery
$(c)$ Semilunar valve	$(iii)$ Between right atrium and right ventricle

Contraction of the right ventricle pumps blood into:

Which chamber of the heart has the thickest wall?

Where does the circulation of oxygenated blood occur in humans?

In the heart, as the action potential reaches the $AV$ node from the $SA$ node, there is a delay of the action potential. This delay is important because: