You are the one defending a thesis.
That's the way it works. You write up your thesis, or disertation, print it on fancy paper, and submit it. Then you get out the PowerPoint (or in my day the slide projector) and stand up in front of a bunch of people who know way more than you do and present it. Then comes the defense. You'd better be ready to ward off the attacks with good, sound science or you are doomed to be flamed to cinders. Usually either your degree or your job hangs in the balance. If you want to be a scientist, get used to it.
Believe me, this place (RL included) is gentle when it comes to a review of science.