Respiratory System : Questions, Quizzes, Facts and more for you

The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. Wikipedia

[Q.] Oxygen carrying blood pigment in certain annelids is
  1. hemoglobin
  2. hemocyanin
  3. Chlorocruorin
  4. haemoerythrin