Final answer:
Iron from the breakdown of hemoglobin is transported in the blood by a protein called transferrin to the red marrow for the production of new red blood cells.
Step-by-step explanation:
Iron molecules released from the breakdown of hemoglobin are transported through the blood by transferrin. Hemoglobin is made up of hemi groups, each containing an iron ion. When hemoglobin is broken down, the iron is recovered and bound to transferrin, a blood protein that carries it to the red marrow. There, iron is used for the synthesis of new erythrocytes (red blood cells). Iron can also be stored in the liver or spleen, primarily in the form of ferritin or hemosiderin, when not immediately needed for erythrocyte production.