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.
The heart is the hollow, muscular organ in the thoracic cavity (chest) that maintains the circulation of blood throughout the body. It is surrounded by a membrane called the pericardium.lood passes from the left atrium through the mitral valve and into the left ventricle. The left ventricle, the largest and most muscular of the four chambers, is the main pumping chamber of the heart.