A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Prepare for questions
Presenting research in alternative forums
Part I. Research and writing: from planning to production

If you're lucky, you'll get questions after your talk, so prepare answers for predictable ones. Expect questions about data or sources, especially if you didn't cover them in your talk. If you address matters associated with well-known researchers or schools of research, be ready to expand on how your work relates to them, especially if you contradict or complicate their results or approach. Also be ready to answer questions about a source you never heard of. The best policy is to acknowledge that you haven't seen it, but that you'll check it out. If the question seems friendly, ask why the source is relevant. Don't prepare only defensive answers. Use questions to reemphasize your main points or cover matters that you may have left out.

Listen to every question carefully, then to be sure you understand the question, pause before you respond and think about it for a moment. If you don't understand the question, ask the questioner to rephrase it. Don't snap back an answer reflexively and defensively. Good questions are invaluable, even when they seem hostile. Use them to refine your thinking.