Q: 156 (SSC/NA)
question_subject:
Science
question_exam:
SSC
stats:
0,8,7,4,1,8,2
keywords:
{'thrombin': [2, 0, 0, 0], 'blood vessels': [3, 0, 0, 1], 'prothrombin': [1, 0, 0, 0], 'fibrinogen': [2, 0, 0, 0], 'blood': [5, 0, 0, 1], 'heparin': [5, 0, 0, 1]}
The correct answer is option 3: Heparin. Heparin is a natural anticoagulant produced by the body. It works by inhibiting the action of thrombin, which is an enzyme involved in the clotting process. Thrombin plays a crucial role in converting fibrinogen into fibrin, which forms a clot.
Option 1: Thrombin is involved in the clotting process, so it does not prevent clotting.
Option 2: Fibrinogen is a protein that is converted to fibrin by thrombin, contributing to clot formation.
Option 4: Prothrombin is a precursor to thrombin and does not prevent clotting.
Therefore, it is clear that the presence of heparin is what prevents blood from clotting in the blood vessels.