Red blood cells transport ---- to the cells.

The heart’s natural pacemaker is termed the 

When the ventricles contract, blood is pumped out from the left ventricle to the aorta and from the right ventricle to the pulmonary artery. This sequence is known as

In humans, typical value for venous blood pressure is about

Blood from systemic circulation enters the heart at the

What prevents blood from flowing backward in veins?

What makes a capillary good at its job?

How thick is the wall of a capillary ?

Which of the followings statement is not true

Followings are features of vein except-