The fluid nature of the membrane is important from the point of view of functions like

Options

A. Cell division and cell growth
B. Endocytosis and cell growth
C. Formation of intercellular junctions
D. All of the above.

Explanation

### Step-by-Step Solution:

1. **Understanding the Fluid Nature of the Membrane**:
- The cell membrane is described by the fluid mosaic model, which indicates that it is not rigid but rather flexible and fluid. This fluidity is crucial for various cellular functions.

2. **Cell Division**:
- The fluid nature of the membrane allows it to deform easily. During cell division, the membrane must stretch and separate to form two new cells. If the membrane were rigid, this process would be hindered, making cell division difficult.

3. **Cell Growth**:
- As a cell grows, it needs to expand in size. The fluid nature of the membrane provides the necessary flexibility for the cell to grow in all directions without breaking.

4. **Endocytosis**:
- Endocytosis is the process by which cells take in large molecules or particles. The fluidity of the membrane allows it to form invaginations or grooves that engulf these substances.
- In phagocytosis (cell eating), the membrane wraps around large particles, while in pinocytosis (cell drinking), it engulfs liquid substances.

5. **Formation of Intercellular Junctions**:
- The fluid nature of the membrane also facilitates the formation of intercellular junctions. These junctions allow cells to connect and communicate with each other, enabling the exchange of molecules and ions.

6. **Conclusion**:
- Given the importance of the fluid nature of the membrane in cell division, cell growth, endocytosis, and the formation of intercellular junctions, the correct answer is option 4: all the above.