What is the approximate duration of a cardiac cycle?

Which of the following organisms show incomplete double circulation?

What happens when blood groups are not compatible during blood transfusion?

What is acute chest pain known as?

Identify the blood vessel of the heart.

The first heart sound occurs due to the closure of the semilunar valves. True or false?

What happens when the ventricular pressure decreases?

Each artery and vein consists of two layers.