The sentence that requires semicolons instead of commas is:
Miss Rachel will teach basic ballet movements such as a pirouette, or a spin, a jete, or a leap, and a reverence, or a bow, to her beginner-level classes.
This sentence is complex because it lists groups of items that contain internal commas, making it difficult to discern the different elements of the list. Using semicolons will help clarify the distinct movements being referred to.