What is the first site of hematopoiesis in a human embryo?

Which of the following is an agranulocyte?

Thrombocytes are essential for coagulation of blood. Comment.

To prevent coagulation,blood stored in a blood bank contains a small amount of:

$A$ person with an unknown blood group under the $ABO$ system has suffered significant blood loss in an accident and requires an immediate blood transfusion. His friend,who has a valid certificate of his own blood type,offers to donate blood without delay. What would be the blood group of the donor friend?

Which one of the following plasma proteins is involved in the coagulation of blood?