<span>Oxygen carried in a hemoglobin molecule is bound to an iron atom.
</span>The red blood cells contain a pigment called hemoglobin, each molecule of which binds four oxygen molecules.
This protein carries oxygen to the cells and carbon dioxide to the lungs.
It is the iron atom<span> that binds </span>oxygen<span> as the blood travels between the lungs and the tissues.</span>
A molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer.
I believe the correct answer would be the third option. Our elements that comprise over 95% of the human body are <span>carbon, hydrogen, oxygen, nitrogen. Carbon and hydrogen is the backbone of any hydrocarbon or organic compound. The cells in our body are made up organic compounds thus our body is mostly composed of carbon and hydrogen. Oxygen is also present in high percent in our body since it is important for the processes of the cells. Also, nitrogen should be present in our body in large amount since it is present in proteins which is found in our body's cells and tissues.</span>
