In clot formation, prothrombin is converted to:

Correct Answer: C

Rationale: Prothrombin becomes thrombin (C), which converts fibrinogen to fibrin.

Correct Answer: B

Rationale: Agranulocytes (B) (lymphocytes, monocytes) lack granules.

Correct Answer: B

Rationale: Emigration (B) is WBC exit from vessels.

Correct Answer: D

Rationale: Type AB (D) are universal recipients, accepting all ABO types.

Correct Answer: D

Rationale: Nervi vasorum are nerves in vessel walls regulating smooth muscle, controlling both vasoconstriction (A) and vasodilation (B), thus (D). Capillary permeability (C) is not nerve-controlled.