Persons with $AB$ blood group are called as "Universal recipients". This is due to:

Which one of the following is necessary to start the clotting of blood?

Which protein is essential for the blood clotting process?

Select the correct statement/s regarding blood groups in human.
$i$. Some genetically determined blood group systems are $ABO$, $Rh$, $Duffy$, $Lewis$, $Bombay$ blood group etc.
$ii$. Three types of agglutinogens are present on surface of human $RBCs$ such as $A$, $B$ and $D$.
$iii$. Individuals with blood group "$AB$ $Rh$ $+ve$" have $A$, $B$ and $D$ antigens on the surface of their $RBCs$ and both antibodies 'a' and 'b' in their plasma.
$iv$. Haemolytic disease of Newborn occurs when mother with $Rh$ $-ve$ blood group conceives $Rh$ $-ve$ foetus.
$v$. Individuals with '$AB$' blood group are called universal donors while those with '$O$' blood group are called universal acceptors, with reference to blood transfusion.

What does a decrease in the number of blood platelets lead to?

$A$ woman of blood group $O$ presented a baby of blood group $O$ which she claimed as her child. She brought a suit against a man of $AB$ blood group as the father of the child. Which statement is correct as per your judgement?