If a dna molecule is compared to a spiral staircase, what parts make up the steps?

I like to think of the DNA molecule strand as a ladder, rather than a spiral staircase. The siderail of the DNA ladder (The DNA "Backbone") consists of the Sugar and Phosphate molecules. The rungs of the ladder (the inner bases) consist of the pairs of Nitrogen Bases - Adenine, Guanine, Cytosine and Thymine. 

hope this helped :)
alisa202

The answer would be dogs.