What are the sides of the DNA ladder made of?

The sides of a DNA ladder are made by bio-polymers which have a more complicated name, polynucleotides. Polynucleotides are made of nucleotides and each of those is made of one of these components. Guanine, Adenine, Thymine, and Cytosine. There is also a base pairing rule. G combines with A, and T combines with C.