The protein which prevents coagulation of blood in the blood vessel is

Which protein is responsible for the formation of antibodies?

Prothrombin is

Name the blood component which is a viscous and straw-coloured fluid.

Globulins are $.......$.

$A$ 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?