<prompt> Hallmark of Barretts epithelium isMucus secreting goblet cellsTransitional columnar epitheliumStratified squamous epitheliumAcid producing parietal cells  <response>: Barretts oesophagus is a metaplastic change in the lining mucosa of the oesophagus in response to chronic gastro-oesophageal refluxThis adaptive response involves a mosaic of cell types, probably beginning as a simple columnar epithelium which becomes specialised with time. The hallmark of specialised Barretts epithelium is the presence of mucus-secreting goblet cells intestinal metaplasia.Ref: Bailey and Love 27e pg: 1081 