Answer:
Purine, Pyrimidine
Step-by-step explanation:
DNA bases consist of two subgroups,
Purines: Adenine and Guanine
And Pyrimidines: Cytosine and Thymine
In genetic material, Adenine bases are always paired with Thymine bases, and Guanine bases are always paired with Cytosine bases. This is why a Purine base will always be paried with a Pyrimidine base.
Fun tip: If you have a hard time remebering which bases are which, a trick I personally use is that Alanine and Guanine are purines, and their code letters (AG) are the symbol for the element silver, which is a type of pure alloy. So AG --> Silver --> Pure --> Purine
If that helps :)