Shave off at least 3 years and you get the average life expectansy.
It is covered with a membrane composed of lipids and proteins, lacks a nucleus, and contains<span> hemoglobin—a </span>red<span>, iron-rich protein that binds oxygen. The </span>red blood cells<span> are highly specialized, well adapted for their </span>primary function<span> of transporting oxygen from the lungs to all of the body tissues.
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