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 a hollow, muscular organ located between the lungs and underneath the breastbone. A muscular wall divides the heart into two sides â the right side and the left side. Each side has two chambers. The two upper chambers of the heart are called the atria. The atria are the filling chambers.