What punctuation mark is commonly used to separate items in a series?

The correct punctuation mark that is commonly used to separate items in a series is the comma. When listing three or more items in a sentence, commas are typically placed between each item to clarify the distinction between them. For example, in the sentence "I bought apples, bananas, and oranges," commas are used to separate the different fruits.

Using commas helps to create a clear and easily readable list, preventing confusion about where one item ends and another begins. While semicolons can be used in more complex lists where the items themselves contain commas, standard lists of simple items rely on commas for separation. Periods are used to end complete sentences, and colons are used to introduce lists or explanations but are not meant for separating items within a list.