What is the purpose of a comma when used in a sentence?

The purpose of a comma in a sentence is primarily to separate items in a list. This helps to clarify meaning and ensure that the reader can easily identify distinct elements being presented. For example, in the sentence "I bought apples, oranges, and bananas," the commas help to clearly differentiate each fruit, preventing any confusion about how many items are being discussed.

While other punctuation marks serve different functions—like question marks indicating a question or periods denoting a complete pause—commas are specifically used for listing and separating items, which is why the selected answer is the most accurate. Additionally, it is important to note that commas can also serve other roles, such as setting off introductory elements or clauses, but their fundamental use in lists is one of the most common functions that helps enhance clarity in writing.