Which of these scientists is not correctly matched with their contributions?

Options

A. Anton Von Leeuwenhoek first saw and described a live cell.
B. Robert Brown discovered the nucleus
C. Matthias Schleiden studied different types of animal cells and reported that cells has a thin outer layer which is today known as the 'plasma membrane'
D. Rudolf Virchow first explained that cells divided and new cells are formed from pre-existing cells

Answer

To solve the question of which scientist is not correctly matched with their contributions, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Identify the Contributions of Each Scientist:**
- **Antoine Von Leeuwenhoek:** He is credited with being the first to observe and describe live cells. This statement is correct.
- **Robert Brown:** He discovered the nucleus, which is a double membrane-bound organelle found in eukaryotic cells. This statement is also correct.
- **Matthias Schleiden:** He is known for his contributions to cell theory, particularly stating that all plants are made of cells. However, the statement provided in the question claims he studied animal cells and described the plasma membrane, which is incorrect. Schleiden focused on plant cells and did not specifically describe the plasma membrane.
- **Rudolf Virchow:** He proposed that all cells arise from pre-existing cells, which is a fundamental concept in cell theory. This statement is correct.

2. **Determine the Incorrect Match:**
- From the analysis above, it is clear that the statement regarding Matthias Schleiden is incorrect. He did not study animal cells or describe the plasma membrane; rather, he contributed to the understanding of plant cells and the formulation of cell theory.

3. **Conclusion:**
- The scientist that is not correctly matched with their contribution is **Matthias Schleiden**.

### Final Answer:
The scientist not correctly matched with their contributions is **Matthias Schleiden**.

---