DNA has four nitrogenous bases:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T)

These bases are the building blocks of the genetic code. They pair up in a specific way: Adenine always pairs with Thymine (A-T), and Guanine always pairs with Cytosine (G-C).

Let me know if you have any other questions about DNA!