Apple Cider Vinegar Don't Promotes Weight Loss:

Claim that ACV refuced weight loss, is completely unsupported by science. ACV is mere a fermented juice and like other fermented products it is only a probiotic which keep stomach and digestive system healthy. ACV which goes under pasteurization procedure even lack this probiotic property because like other sterilization procedure, pasteurization kill bacteria from juice.
There is simply no science to back up the claim that it helps reducing weight.

Difference between Prebiotic and Probiotic:
Probiotic means live bacteria while Prebiotic means plant fibres which give benefits to bacteria already living in Gastrointestinal tract.