Who proposed a modification in the cell theory ?

Options

A. Schleiden and Schwann
B. Rudolf Virchow
C. Robert Hooke
D. Marcello Malpighi.

Answer

To answer the question "Who proposed a modification in the cell theory?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cell Theory**:
- The original cell theory was formulated by scientists Matthias Schleiden and Theodor Schwann. They proposed that all living organisms are made up of cells and that cells are the basic unit of life.

2. **Identifying the Modification**:
- The original cell theory included the idea that new cells arise from existing cells, but this specific postulate was later added by Rudolf Virchow.

3. **Rudolf Virchow's Contribution**:
- Rudolf Virchow is known for his famous phrase "Omnis cellula e cellula," which means "all cells come from cells." This statement emphasized that new cells are formed from the division of pre-existing cells.

4. **Conclusion**:
- Therefore, the modification in the cell theory was proposed by Rudolf Virchow, who added the concept that all new cells arise from pre-existing cells.

### Final Answer:
Rudolf Virchow proposed a modification in the cell theory.

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