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Given below are four statements (i-­iv) regarding human blood circulatory system. (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. Which two of the above statements is/are correct?

Correct answer: A. (i) and (iv)

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

Explanation

The correct statements (i)and (iv) are correct.(i) Arteries are thick-walled and have narrow lumen as compared to veins. Arteries are blood vessels that carry oxygenated blood away from the heart to various parts of the body. They have thick walls containing smooth muscle and elastic fibers, which allow them to withstand the high pressure generated by the heart's pumping action. Arteries also have a smaller lumen (the central opening through which blood flows) to maintain the blood pressure and ensure proper blood flow to the tissues. (iv) Calcium ions play a very important role in blood clotting.The statement about calcium ions is correct. Calcium ions play a crucial role in the process of blood clotting or coagulation. When there is an injury or damage to blood vessels, a series of complex reactions involving various clotting factors take place, ultimately leading to the formation of a blood clot to prevent excessive bleeding. Calcium ions are essential for the activation of clotting factors and the formation of a stable blood clot.

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