In anatomy and physiology, what is hemoglobin and how does it carry oxygen? a) Hemoglobin is a type of white blood cell that carries oxygen by binding it to iron molecules. b) Hemoglobin is a protein found in red blood cells that carries oxygen by binding it to heme groups. c) Hemoglobin is a hormone that regulates oxygen levels in the blood by inhibiting its release from red blood cells. d) Hemoglobin is a neurotransmitter that facilitates the transport of oxygen across synaptic clefts.