The heart of a healthy man beats normally per minute:

The mitral valve in mammals guards the opening between:

Which organ is important as a large reservoir of erythrocytes?

The apex beat of the heart is synchronous with:

The blood pumped by the $A$ ventricle enters the $B$ artery,whereas the $C$ ventricle pumps blood into the $D$. Choose the correct option for $A, B, C$ and $D$.

The opening of the pulmonary vein is without a valve because