Which of the following enzymes is responsible for unwinding the DNA double helix during replication?

The enzyme responsible for unwinding the DNA double helix during replication is called helicase.

Here's a step-by-step explanation:

1. The process begins at specific locations in the DNA called origins of replication.

2. The enzyme helicase attaches to the DNA at the origin of replication and travels along the DNA, breaking the hydrogen bonds between the base pairs. This action unwinds the DNA double helix into two single strands.

3. As the DNA unwinds, other proteins and enzymes come in to stabilize the single strands and prevent them from winding back into a double helix.

4. Once the DNA is unwound, the process of replication can begin, with other enzymes like DNA polymerase synthesizing new strands of DNA.