Multiple choice Which of the following is INCORRECT regarding blood coagulation in human beings? Platelets are the fragments of megakaryocytes. Primary haemostasis initially involves vasodailation. Platelet activation stimulates production of thromboxane. Fibrin monomers gets cross-linked by factor XIIIa. Clotting is initiated by exposure of tissue factor-bearing cells to plasma clotting factors. Reveal answer Fill a bubble to check yourself B Correct answer Explanation Primary haemostasis initially involves vasoconstriction in response to vascular damage, which limits blood loss, and subsequent platelet adhesion to the damaged area and activation due to exposure of subendothelial matrix.