Read the following statements:
(i) During a cardiac cycle, both ventricles pump out approximately $70\text{ml}$ of blood called stroke volume.
(ii) Cardiac output can be defined as volume of blood pumped out by both ventricle per minute.
(iii) Cardiac output of an athlete will be higher than that of an ordinary man.
(iv) During each cardiac cycle two prominent sounds are produced.
How many statements are correct?

The correct option is C Two
During a cardiac cycle, each ventricle pumps out approximately $70\text{ml}$ of blood which is called the stroke volume.
The stroke volume multiplied by the heart rate (number of beats per minute) gives the cardiac output. Therefore, the cardiac output can be defined as the volume of blood pumped out by each ventricle per minute and averages $5000\text{mL}$ or $5\text{litres}$ in a healthy individual.

The body has the ability to alter the stroke volume as well as the heart rateand thereby, the cardiac output. For example, the cardiac output of anathlete will be much higher than that of an ordinary man.

During each cardiac cycle, two prominent sounds are produced which can be easily heard through a stethoscope. The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves where as the second heart sound (dub) is associated with the closure of these semilunar valves. These sounds are of clinical diagnostic significance.