DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.
The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs. In the human heart there is one atrium and one ventricle for each circulation, and with both a systemic and a pulmonary circulation there are four chambers in total: left atrium, left ventricle, right atrium and right ventricle.
Blood circles through the heart, which pumps it to the lungs where it picks up oxygen - this is the pulmonary circulation. The heart then pumps the oxygen-rich blood to the rest of the body - this is the systemic circulation. Pulmonary Circulation.