DNA helicase is an enzyme responsible
for (what) the double
strand of DNA.

Helicases are enzymes that are responsible for untwisting the double helix at the replication forks, separating the two strands and making them available to serve as templates for DNA replication

Explanation:

really dont know just need some points

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides