Which of the following is not true ?

Options

A. Movement is considered one of the important life processes
B. Growth, repair, or replacement of cells is known as responsiveness
C. When unspecialized cells become specialized, the process is known as differentiation
D. Structure of a body part determines its function

Explanation

To determine which statement is not true, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Statement A: Movement is considered one of the important life processes.**
- This statement is true. Movement is a fundamental characteristic of living organisms, as it allows them to interact with their environment, search for food, escape predators, and perform other essential functions.

2. **Statement B: Growth, repair, replacement of cells is known as responsiveness.**
- This statement is not true. Growth, repair, and replacement of cells are processes related to development and maintenance of the organism, while responsiveness refers to how organisms react to external stimuli. Therefore, this statement is incorrect.

3. **Statement C: When unspecialized cells become specialized, the process is known as differentiation.**
- This statement is true. Differentiation is the process by which unspecialized cells develop into specialized cells that perform specific functions, such as muscle cells, nerve cells, and liver cells.

4. **Statement D: Structure of body part determines its function.**
- This statement is true. This principle is often referred to as the "structure-function relationship" in biology, where the physical structure of a body part is closely related to its function.

### Conclusion:
After analyzing all the statements, the statement that is not true is **B: Growth, repair, replacement of cells is known as responsiveness.**