Final answer:
Metaplasia is the change of one cell type into another, often due to irritation or inflammation, and a common example of this process is Barrett's esophagus.
Step-by-step explanation:
Metaplasia is a process where one mature type of cell changes into another mature type of cell. This can often be a response to chronic irritation or inflammation, allowing an organ to adapt to a new stress, but it may also predispose tissues to cancer. A classic example of metaplasia is Barrett's esophagus, where the normal squamous epithelium of the esophagus changes into a columnar epithelium, a characteristic of the stomach or intestinal lining, often due to chronic acid reflux.