This is due to Chargaff's rules, which state that:
* The amount of adenine (A) is always equal to the amount of thymine (T).
* The amount of guanine (G) is always equal to the amount of cytosine (C).
This pairing is because adenine forms two hydrogen bonds with thymine, and guanine forms three hydrogen bonds with cytosine. This complementary base pairing is crucial for the structure and function of DNA.
