The phrase "are a part" can be substituted with numerous synonyms to enhance the richness of language and avoid repetition. Some of the synonyms of "are a part" include "form a constituent," "compose," "constitute," "make up," "belong to," "inherent," "pertain to," and "be included in." These synonyms help to add diversity and creativity to sentences, making them sound more interesting and engaging. Choosing the right synonym depends on the context of the sentence and the type of writing style used. Using synonyms for "are a part" helps to avoid redundancy and keep the reader interested in the content.