The presentation is drawing to a close, the salient points having been made, and the speaker concludes with, "Are there any questions?" Or the last slide (mercifully) appears and says, "Questions?"
This is the least effective, most dangerous way to end a presentation.
That final question may be too detailed, too basic or advanced for the majority of the audience, off topic, downright hostile or one you can't answer. Is that the last thing you want your audience to hear before they walk away?
WHAT IF YOU ASK THE QUESTION?
Now if your presentation ends with you asking a question of the audience, that's an entirely different matter. But make it a purposeful question, designed to encapsulate your message, be provocative or call the audience to action. Make it a question that will have the audience buzzing, long after they've left the room.