Why do RBCs need to respire?
Red Blood Cells did to respire to be free to carry Oxygen
Respire can be defined as to breath again. In the lungs RBC respire, Carbon Dioxide is released from the RBC into the lungs and the Hemoglobin is then able to absorb Oxygen from the lungs.
If the RBC did not respire in the lungs the blood would not be able to carry fresh Oxygen to the bodies cells, and the cells would die.