The breakdown product of haemoglobin is

Which of the following figures correctly represents the path of a closed circulatory system?

Cords of Billroth are blood-filled spaces found in which of the following organs?

Match the following columns:

Column $- I$	Column $- II$
$a$. Bicuspid valve	$p$. Brain
$b$. Nephron	$q$. Liver
$c$. Alveoli	$r$. Heart
$d$. Cerebrum	$s$. Kidney
	$t$. Lungs

Given below are four statements $(i-iv)$ regarding the human blood circulatory system.
$(i)$ Arteries are thick-walled and have a narrow lumen as compared to veins.
$(ii)$ Angina is acute chest pain when the blood circulation to the heart muscle is reduced.
$(iii)$ Persons with blood group $AB$ can donate blood to any person with any blood group under the $ABO$ system.
$(iv)$ Calcium ions play a very important role in blood clotting.
Which two of the above statements are correct?

Statement-$I$ :- The body has the ability to alter the stroke volume as well as heart rate and thereby the cardiac output.
Statement-$II$ :- During each cardiac cycle two prominent sounds are produced which can not be easily heard through a stethoscope.