Which of the following vertebrate organs receives only oxygenated blood?

Which of the following statements are wrong?
$(i)$ Leucocytes disintegrate in the spleen and liver.
$(ii)$ $RBC$,$WBC$ and blood platelets are produced by bone marrow.
$(iii)$ Neutrophils bring about destruction and detoxification of toxins of protein origin.
$(iv)$ The important function of lymphocytes is to produce antibodies.

Which organ remains functional for a few hours even after clinical death?

If cardiac output is $4200 \text{ ml/min}$,then $x$ beats/min is the heart rate and $y$ is the term for pulse rate.

$A$: In an open circulatory system,the volume of blood is high,but blood pressure is low and irregular.
$R$: In a closed circulatory system,the volume of blood is limited,and blood pressure is high and regular.

The given figure shows the schematic plan of blood circulation in humans with labels $A$ to $D$. Identify the label and give its function/functions.