Answer:
Hemoglobin
Step-by-step explanation:
The blood is a living tissue made up of cells. These cells include red blood cells or erythrocytes, white blood cells or leukocytes, platelets etc. However, the red blood cells or erythrocytes contains a protein that confers its red coloration upon it. This protein is called HEMOGLOBIN.
Hemoglobin is a protein that contains iron (Fe) element in the core of its structure. Hemoglobin is capable of forming a bond with oxygen molecule, hence, it helps the red blood cells to carry oxygen across the body.