Which term represents normal tissue that has become abnormal?

The term that best represents normal tissue that has become abnormal is metaplasia. This biological process involves the transformation of one type of mature tissue into another type of tissue, usually in response to chronic irritation or injury. In this situation, the cells adapt to a new environment or conditions, but this adaptation can lead to abnormalities in tissue structure and function.

For example, in the respiratory tract, normal columnar epithelial cells might be replaced by squamous cells due to long-term exposure to irritants like cigarette smoke. While metaplasia can be reversible if the irritant is removed, it indicates a significant change from the tissue’s original state, highlighting a form of abnormality.

In contrast, malignant tumors represent a more severe deviation from normal tissue characterized by uncontrolled cell growth, often leading to cancer. Contact inhibition is a term used to describe a property of normal cells to stop dividing when they come into contact with one another, which is not an abnormal tissue condition. Motility refers to the ability of cells to move, which does not directly address tissue abnormality.