Do you actually have to put acknowledgments in the Extended essay? If so... who do you acknowledge?! I've done a history one so all the stuff I used is in my bibliography, so am a bit confused about this!
you can do it, i don't remember if you had to. below the headline acknowledgements you are supposed to write if you want to thank someone, and i don't think that it has to be someone that has helped you directly. if you got all your info from books and you have put them in the bibliography that should be enough. but like i said i don't remember..if you do however you can just thank family, friends or something for their support, maybe the librarian (if there was one) for helping you find the right books, or maybe a teacher if you have ahd one that has helped you and given you feedback.
Of-course you don't need one. It's just a nice thing to do - to acknowledge the help of your supervisor, or any other helpful people - who have made it all possible (tear wipe).
I had one. Many didn't.