Interrogative marks, also known as question marks (?), are punctuation symbols used at the end of a sentence to indicate that it is a question. They help readers understand that the sentence is seeking information or clarification. For example, in the sentence "What time is the meeting?", the question mark signals that the speaker is asking for details. In English grammar, interrogative marks are essential for distinguishing questions from statements. They are typically placed after direct questions but are not used in indirect questions. For instance, "She asked if I was coming" does not require an interrogative mark, while "Are you coming?" does.