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 central organ of the circulatory system, and pumps blood into the blood vessels which carry it to all the body parts. The average heart rate in a normal person is 72 beats per minute, so one can imagine the speed at which blood flows through the body.