What is an interjection commonly used for in writing?

An interjection is primarily used in writing to express strong emotions or exclamations, capturing the author's or speaker's feelings in a concise and impactful way. Words like "wow," "ouch," or "hey" are typical examples of interjections, and they are often accompanied by punctuation, such as exclamation marks, to emphasize the emotion being conveyed. Their purpose is to add a layer of emotion to the text, making it more dynamic and relatable to the reader.

In contrast, the other options relate to different functions in writing: transitions between ideas are typically accomplished with conjunctions or transitional phrases, establishing the main idea usually involves topic sentences or thesis statements, and modifying nouns is the role of adjectives or adverbs. Thus, the unique function of interjections distinctly aligns with the option focused on expressing feelings or exclamations.