**Core Concept**
Change in structure and functions of a tissue is a fundamental concept in pathology and histology. This term refers to the process by which a normal tissue undergoes a transformation, leading to changes in its cellular composition, architecture, and function. This change can be adaptive or pathological.

**Why the Correct Answer is Right**
Homeostasis is maintained by the body through various mechanisms, but when these mechanisms fail, tissues can undergo changes in structure and function. This process can be triggered by various factors such as injury, inflammation, or neoplastic growth. The changes in tissue structure and function can be observed at the cellular level, where there may be an increase in cell number, size, or shape, or a change in the types of cells present. These changes can lead to a loss of normal tissue function, resulting in disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option does not accurately describe the change in structure and function of a tissue. Atrophy refers to a decrease in size of a tissue or organ, which is not the correct answer.
**Option B:** This option is incorrect as it refers to the process of cell division, which is not directly related to the change in structure and function of a tissue.
**Option C:** This option is incorrect as it refers to the process of tissue repair, which is a response to injury, but does not accurately describe the change in structure and function of a tissue.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize that changes in tissue structure and function can be a hallmark of various diseases, including cancer, where the tissue undergoes a transformation to become malignant. Understanding these changes is crucial for diagnosis and treatment.

**Correct Answer: D. Metaplasia. Metaplasia is a change in structure and function of a tissue.**