<prompt> Biopsy of the lower oesophagus in a patient with chronic reflux demonstrates epithelial metaplasia. Which of the following cell types was most likely observed in the involved areas?Ciliated columnar epitheliumCiliated columnar epitheliumKeratinizing squamous epitheliumNonciliated columnar epithelium  <response>: The medical condition is Barretts esophagus, in which the normally nonkeratinizing squamous epithelium of the esophagus undergoes metaplasia to gastric or intestinal-like epithelium composed of nonciliated columnar epithelial cells. 