The phrase "are due to" is commonly used when explaining the cause of something. However, there are many synonyms that can be used to add variety to your writing. Some options include "stem from," "result from," "arise from," "are caused by," "originate from," "are attributable to," and "are provoked by." Each of these phrases conveys a slightly different nuance, so consider using them strategically to communicate your intended meaning. By varying the language you use to explain causation, you can make your writing more engaging and effective.