Hello everyone i am new here. I have been solidworks for some time but i am not an expert.

I have been given an assignment to model a soda bottle and do stress analysis on it. I have done the modelling but when i try to start the analysis, it gives me an error saying that multi-body simulation is not supported right now. i checked the net and the forums and came to know that i have to combine all the parts of the model. when i try to combine it gives me an error saying that "unable to create single body that is the sum of the input bodies". what i have come to understand till now is that i need to merge the features on the bottle with the body of the bottle. but when i merge the features, it does not merge. Can somebody please help me with this problem. Here is the link to the model- FINAL2.SLDPRT - Google Drive . it would be really helpful if someone can suggest something.