Which of the following is not a process in which extracellular materials are brought into the cell?

Options

A. Pinocytosis
B. Phagocytosis
C. Exocytosis
D. Endocytosis

Explanation

To determine which of the following is not a process in which extracellular materials are brought into the cell, we need to analyze the different processes of material uptake and release in cells.

### Step-by-Step Solution:

1. **Understanding Endocytosis**:
- Endocytosis is the process by which cells take in materials from the extracellular environment. This can occur in two main forms: phagocytosis and pinocytosis.
- **Phagocytosis**: This is often referred to as "cell eating." In this process, the cell membrane engulfs large particles or food materials, forming a phagosome (food vacuole).
- **Pinocytosis**: Known as "cell drinking," this process involves the uptake of fluids and small solutes. The cell membrane invaginates to form small vesicles that bring in extracellular fluid.

2. **Identifying Exocytosis**:
- Exocytosis is the opposite of endocytosis. It is the process by which cells expel materials. In this case, vesicles containing waste or other materials fuse with the cell membrane and release their contents outside the cell.
- Since exocytosis involves the removal of materials from the cell rather than the intake, it does not fit the criteria of bringing extracellular materials into the cell.

3. **Conclusion**:
- Among the processes discussed, phagocytosis and pinocytosis are both methods of bringing materials into the cell, while exocytosis is a method of expelling materials from the cell. Therefore, the process that is not involved in bringing extracellular materials into the cell is **exocytosis**.

### Final Answer:
**Exocytosis is not a process in which extracellular materials are brought into the cell.**

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