Answer: repetition
Explanation: The difference between repetition and parallelism is mainly that parallelism is the repeating of words with just slight adjustments each time. Repetition is repeating the SAME thing "over and over and over" again (see what I did there, THAT was repetition). Other examples of repetition are:
Time after time
Heart-to-heart
Hand in hand
Get ready, get set, go
Home sweet home
It is what it is
parallelism is changing it slightly each time
Repetition is often used to grab the readers attention or make the point(s) more stronger or more obvious