A question mark is placed at the end of a sentence that is a direct question. In most instances, two questions become two sentences, with a question mark at the end of each sentence.
Two Questions, One Mark
Two questions can be rephrased to create one sentence with one question mark. You can ask two questions: Do you want meat? Do you want fish? An alternative is: Do you want meat or fish? Another example of using one mark for two questions, from the University of Maryland Writing Center, uses a quotation: Did Fadumo ask, “Are we going to the Washington Monument?”
One Sentence, Many Questions
The Capital Community College Foundation offers this example of how to combine one question with several follow-up questions into one sentence: "Who is responsible for executing the plan? the coach? the coaching staff? the players?" Some writers, however, instead follow the rule that each follow-up question should begin with a capital letter.