The phrase "are variable" refers to something that is subject to change or inconsistency. There are several synonyms that can be used in place of this phrase, such as "fluctuate," "vary," "inconstant," "unpredictable," "changeable," and "volatile." Each of these words encompasses the idea that something is not stable or fixed, and may shift or alter over time. Using synonyms can add variety and precision to one's vocabulary, while also helping to better convey the intended meaning. When describing a situation or condition that is not constant, it can be useful to explore different synonyms to find the word that best fits the context.