Given below are four statements (A-D) regarding human blood circulatory system A. Arteries are thick-walled and have narrow lumen as compared to veins. B. Angina is acute chest pain when the blood circulation to the brain is reduced. C. Persons with blood group-AB can donate blood to any person with any blood group under ABO system. D. Calcium ions play a very important role in blood clotting. Which two of the above

Step-by-step solution

Arteries are the blood vessels which carry blood away from the heart. In comparison to veins, arteries have narrow lumen and more muscular thick walls to bear the pressure of pumping action of heart. Angina is constricting chest pain caused due to reduced blood supply to the heart wall. Persons with blood group-AB are universal acceptor, while those with blood group-O are universal donor. Calcium ions are required during blood clotting for the conversion of prothrombin into thrombin, and fibrinogen into fibrin.