Answer:
The DNA nucleic acids contain four bases which are Adenine (A), Thymine (T), Cytosine (C) and Guanine (G).
Adenine pairs with Thymine
Cytosine pairs with Guanine
The term double helix means two strands which are parallel to each other and are intertwined from a common point. The structure of the DNA is a double- helix consisting of phosphate sugar which makes the backbone of the strands. The two strands are joined by hydrogen bonds present between the nucleic acids.