One of the times I find difficult when giving a presentation is dealing with questions.
One of my presentation techniques I use to handle difficult questions is to agree with the questioner to relax the audience and remove some of the heat from the question.
Listen to the question carefully. Pause for a second and then say, “I agree, there is a lot in what you say, but …”This technique tends to calm down an irritated questioner and makes him feel that they are sensible and that you agree with much of what they have had to say. Avoid answering to quickly or you may appear to be too clever. The audience wants to be able to relate to the presenter.