DNA replication is the process by which DNA makes a copy of itself during cell division. 1  The first step in DNA replication is to âunzipâ the double helix structure of the DNA molecule.
The heart is a muscular organ in humans and other animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen and nutrients, and also assists in the removal of metabolic wastes. The heart is located in the middle compartment of the mediastinum in the chest.
Human Anatomy Â» Body Systems Â» Cardiovascular System Â» Anatomy of Heart. Heart is a hollow muscular organ, which is somewhat pyramidal in shape. It lies within the pericardium in the mediastinum. It lies free within the pericardium except at its base where it is connected to great blood vessels.