Who was the scientist to introduce $ABO$ blood groups?

Which one of the following cells secrete heparin,histamine and serotonin?

Match the following:

Column-$I$	Column-$II$ and Column-$III$
$X$. $RBC$	$R$. Lack of nucleus,$A$. $5-5.5$ Million
$Y$. Monocytes	$P$. Nucleated,$C$. $6-8\%$
$Z$. Eosinophil	$Q$. Granulocyte,$B$. $2-3\%$

Vitamin-$K$ is essential for:

Which of the following blood corpuscles are least in number,in human beings?

Which of the following are erythropoietic organs?
$I$. Liver
$II$. Lymph node
$III$. Spleen
$IV$. White bone marrow
$V$. Red bone marrow
Choose the correct option.