The
Blood<span> moves in the heart through two large veins, the
inferior and superior vena cava, and exhausting oxygen-poor blood from the body into the right atrium. The pulmonary vein discharges oxygen-rich blood, from the lungs into the left atrium.</span>
How do genes direct the production of proteins?: MedlinePlus Genetics
y/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/a/overview-of-eukaryotic-gene-regulation
Overview: Eukaryotic gene regulation (article) | Khan Academy
