Question

why red blood cells are only in red colour?

Answer 1

Answer:

They are red in colour because of the red pigment present in it called haemoglobin

Answer 2

Explanation:

Blood is red because it is made up of cells that are red, which are called red blood cells. ... Each hemoglobin protein is made up subunits called hemes, which are what give blood its red color. More specifically, the hemes can bind iron molecules, and these iron molecules bind oxygen.