<prompt> Barretts esophagus isLower esophagus lined by columnar epitheliumUpper esophagus lined by columnar epitheliumLower esophagus lined by ciliated epitheliumLower esophagus lined by pseudo stratified epithelium  <response>: Barretts esophagus is specialized columnar metaplasia that replaces the normal squamous mucosa of the distal esophagus in some persons with GERD. Barretts epithelium is a major risk factor for adenocarcinoma of the esophagus and is readily detected endoscopically, due to proximal displacement of the squamocolumnar junction.Ref: Harrison; 19th edition; Page no: 1895 