Answer:
Two complementary strands of DNA come together thanks to hydrogen bonding between the nitrogenous bases that allows DNA to make a ladder-like form that twists into the famous double-helix. ... In DNA, there are four nitrogenous base options: adenine (A), thymine (T), cytosine (C) and guanine
Explanation:
In biology, specifically in terms of genetics and DNA, complementary means that the polynucleotide strand paired with the second polynucleotide strand has a nitrogenous base sequence that is the reverse complement, or the pair, of the other strand.
So, for example, the complement of guanine is cytosine because that's the base that would pair with guanine; the complement of cytosine is guanine. You would also say the complement of adenine is thymine, and vice versa.
This is true along the entire DNA strand, which is why the two strands of DNA are called complementary strands. Each and every base on a single strand of DNA is going to see its complement matched with it on the other strand.
