Hi. I've only just started reading on M-theory. I'm otherwise a lay person so I'm going to have some basic questions. Here's my first. Standard Model has 17 elementary particles right? But doesn't M-theory say there's 18? Or 36 if you include the symetrical ones. So am I missing one partical? Or are the theories talking about something different. I can see that my book mentions the graviton, which isn't in the standard model, so maybe that's the difference? Thanks!