Answer & Explanation:
The DNA is a double-stranded helix with an antiparallel disposition going from 3' to 5' in one strand and otherwise in the other. It's made of nucleotides, that at the same time are made of one nitrogen base, a sugar and a phosphate group. The bases are paired between purines (Adenine and Guanine) and pyrimidines (Cytosine and Thymine) and they correspond one from each group (Adenine with Thymine and Cytosine with Guanine). This correspondency allows the cell to replicate and have the same information in every copy of the DNA.