I am not young enough to know everything.
– Oscar Wilde
We never know everything. We never will. Even experts get stumped. There are a lot of great questions. Yet so many people say, “I get so nervous before a presentation because I’m afraid I’ll get asked something I don’t know.“ So?
What you get asked can’t hurt you. What you say in response can. Be comfortable in not knowing something, it’s human. Be ready to openly admit it and offer to help find the answer, or to help find someone who knows the answer. It’s more authentic, and therefore more appealing.  Even subject matter experts explore with, and learn from, their audiences. And it’s best when the presenters are completely transparent about their limitations; trying to cover up or make something up is also quite transparent, so don’t go there and risk compromising your credibility unnecessarily.
Just because you’re the speaker does not automatically mean you’re omniscient. “I don’t know, I can find out for you” is a brilliant answer!

Beth Levine