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 regarding which scientist is not correctly matched with their contributions, we will analyze each option provided.

### Step 1: Analyze Anton Von Leeuwenhoek
- **Contribution**: First saw and described live cells.
- **Evaluation**: Anton Von Leeuwenhoek is indeed credited with being the first to observe and describe live cells using a microscope he developed. This match is correct.

### Step 2: Analyze Robert Brown
- **Contribution**: Discovered the nucleus.
- **Evaluation**: Robert Brown is known for discovering the nucleus in plant cells. This contribution is accurately matched.

### Step 3: Analyze Matthias Schleiden
- **Contribution**: Studied different types of animal cells and reported that cells have an outer layer known as the plasma membrane.
- **Evaluation**: Matthias Schleiden is actually known for his contributions to the cell theory, specifically regarding plant cells. The statement about the plasma membrane is not attributed to him, making this match incorrect.

### Step 4: Analyze Rudolf Virchow
- **Contribution**: Explained that cells divide and new cells are formed from pre-existing cells.
- **Evaluation**: Rudolf Virchow is indeed recognized for this contribution, which is a key part of the cell theory. This match is correct.

### Conclusion
Based on the evaluations:
- The incorrect match is with **Matthias Schleiden**, as he did not study animal cells or report on the plasma membrane. Instead, he contributed to the understanding of plant cells and the cell theory.

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

---