Question

Given below are four statements (i-iv) regarding human blood circulatory system. Choose the option representing the correct statements.
(i) Arteries are thick-walled and have narrow lumen as compared to veins
(ii) Angina is acute chest pain when the blood circulation to the brain is reduced
(iii) Persons with blood group AB can donate blood to any person with any blood group under ABO system
(iv) Calcium ions play a very important role in blood clotting

• A. (i) and (iv)
• B. (i) and (ii)
• C. (ii) and (iii)
• D. (iii) and (iv)

Answer 1

The correct option is A (i) and (iv)

Arteries are thick-walled and have narrow lumen as compared to veins.
Angina is chest pain or discomfort caused when your heart muscle doesn't get enough oxygen-rich blood.
AB blood group person have both antigens A and B, so will be having both anti-A and anti-B antibodies in the plasma. Due to the presence of both antibodies against antigen A and B, AB blood group cannot donate blood to anyone except the AB blood recipient. But the AB blood group is a universal recipient.
Calcium plays an important role in blood clotting. Clotting requires calcium ions (Ca²⁺) (which is why blood banks use a chelating agent to bind the calcium in donated blood so the blood will not clot in the bag).