What is DNA?

Deoxyribonucleic acid (DNA) is a molecule composed of two chains (made of nucleotides) that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.

Source: Wikipedia

Every computer systems requires code to work. In computers, the code is called software. The software runs the hardware to produce a process. In the same way, DNA is the software for any organism. Pre-program code that a designer created for evereything to have funtionality.