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.
Human circulatory system has a four- chambered heart with two separate atria two separate ventricles. The main function of heart is to pump blood to all the body parts through the blood veins. The human heart maintains two types of circulation cycles called pulmonary circulation and systemic circulation.