Answer:
Glacial striation is your answer
The answer would be - It untwists the double helix and separates the two DNA strands. A helicase is an enzyme used to separate strands of a DNA double helix by breaking hydrogen bonds between annealed nucleotide bases.
The atria and ventricles work together, alternately contracting and relaxing to pump blood through your heart. ... The electrical activity spreads through the walls of the atria and causes them to contract. This forces blood into the ventricles. The SA node sets the rate and rhythm of your heartbeat.