Question

A pigment that causes red colour of blood​

Answer 1

Hemoglobin

Red blood cells: The blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).

Answer 2

Answer:

Human blood is red because of the protein hemoglobin, which contains a red-colored compound called heme that's crucial for carrying oxygen through your bloodstream. Heme contains an iron atom which binds to oxygen; it's this molecule that transports oxygen from your lungs to other parts of the body.

hope it helps u