Medicine The blood in the vessels normally does not clot because – A Vitamin K antagonists are present in plasma B Throbin has a positive feedback on plasminogel C Sodium citrate in plasma chelates calcium ions D Vascular endothelium is smooth and coated with glycocalyx 💡 Explanation The blood in the vessels normally does not clot because - ✓ Correct Answer: D. Vascular endothelium is smooth and coated with glycocalyx