The answer would be the first one
An organism<span> is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In </span>multicellular organisms<span>, including humans, all cells, </span>tissues<span>, </span>organs<span>, and </span>organ<span> systems of the body work together to maintain the life and health of the </span>organism<span>.</span>
The unusual property that cytochromes have in common with hemoglobin or myoglobin is that all of them contain heme groups. Cytochromes are heme-containing electron transport enzymes which are essential for the oxidative metabolism necessary to generate adenosine triphosphateas well as for the oxidative degradation of drugs and endogenous substrates.
