The phrase "rise and falls" is commonly used to describe fluctuations or changes in things like temperature, stock prices, or emotions. However, there are many synonyms that can be used to convey similar ideas. "Fluctuations" implies a back-and-forth movement, while "variation" suggests changes over time. "Ups and downs" is a more casual way of saying rise and falls, while "oscillations" refers to regular changes around a central point. "Shifts" suggests a movement in a particular direction, and "undulations" implies a smooth, wave-like movement. With so many options, writers can choose the word that best conveys the intended meaning of the rise and falls in question.