More specifically, it's a deoxyribonucleic acid, a long, complex polymer composed of repeating subunits called nucleotides. Each nucleotide consists of:

* Deoxyribose sugar: A five-carbon sugar.

* Phosphate group: A negatively charged group.

* Nitrogenous base: One of four bases: adenine (A), guanine (G), cytosine (C), or thymine (T).

The sequence of these bases along the DNA molecule carries the genetic information.