Final answer:
Fibrinogen's absence in normal hematocrit prevents blood from forming a clot, as fibrinogen is essential for the coagulation process that stops bleeding.
Step-by-step explanation:
In normal hematocrit, the absence of fibrinogen eliminates the ability of the blood to form a clot. Fibrinogen is a soluble protein produced by the liver that is critical for the coagulation process. During coagulation, thrombin, an essential enzyme, converts fibrinogen into fibrin, which then forms a mesh. This mesh traps more platelets and erythrocytes, effectively creating the blood clot necessary to stop bleeding. Without fibrinogen, this mechanism cannot occur, and the main function of blood clotting is impaired, leaving the body vulnerable to continued bleeding from wounds.