**Core Concept**
Metaplasia is a reversible, adaptive change in which one adult cell type is replaced by another adult cell type, often in response to chronic irritation or injury. This process involves a change in the type of cells lining a tissue, usually to a more resistant or less sensitive type.

**Why the Correct Answer is Right**
Metaplasia can occur in various tissues, including the respiratory, gastrointestinal, and urinary systems. For example, in the respiratory system, chronic irritation can lead to the replacement of ciliated pseudostratified columnar epithelium with squamous epithelium, a more resistant type. This process is often seen in conditions such as chronic bronchitis or laryngitis. In the gastrointestinal system, metaplasia can occur in response to chronic irritation, such as in the case of gastric ulcers, where the normal gastric epithelium is replaced by intestinal-type epithelium.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because metaplasia can indeed occur in this type of tissue, often in response to chronic irritation or injury.
**Option C:** This option is incorrect because metaplasia can also occur in this type of tissue, such as in the case of Barrett's esophagus, where the normal squamous epithelium of the esophagus is replaced by intestinal-type epithelium.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that metaplasia is a reversible change, and it can often be reversed if the underlying cause of chronic irritation or injury is addressed. For example, if a patient with chronic bronchitis stops smoking, the ciliated pseudostratified columnar epithelium may return to normal.

**Correct Answer: D.**