Question

The colour of red blood cells is due to __________.

Answer 1

1. Hemoglobin (Hb or Hgb ) is an iron-containing protein present in the erythrocytes or red blood cells (RBC) of almost all vertebrates.
2. The blood cells are red due to the interaction between iron and oxygen.
3. Hence, the red colour of the red blood cells is due to the presence of hemoglobin.

Final answer : The colour of red blood cells is due to hemoglobin.