What is the main component of blood plasma?

Biological marriage of one of the following should be avoided:

By using the stain methylene blue,the . . . . . . can be differentiated from other corpuscles.

Which of the following is true for blood group '$O$'?

Blood group $O$ has:

$A -$ Fibrinogen is needed for the clotting of blood,and globulins are involved in defense mechanisms of the body.
$R -$ Factors for the coagulation of blood are present in the blood in an inactive form.