Answer:
To unwind the duplex DNA.
Step-by-step explanation:
DNA helicases are a type of enzymes that play an important role in unwinding double-stranded DNA during the process of DNA replication.
These enzymes use the energy from ATP hydrolysis to perform their function.
By causing the separation of the double-stranded DNA, the DNA helicases make the single-stranded DNA available for the DNA polymerases to start adding the complementary nucleotides.