Cell theory was first modified by

Options

A. Schleiden
B. Brown
C. Schwann
D. Grew

Answer

To determine who first modified the cell theory, we can follow these steps:

### Step 1: Understand the Original Cell Theory
The original cell theory was proposed in the early 19th century, primarily by scientists Matthias Schleiden and Theodor Schwann. Schleiden stated that all plant tissues are made up of cells, while Schwann extended this idea to animal tissues.

### Step 2: Identify the First Modification
The question asks for the first modification of the cell theory. After the initial formulation by Schleiden and Schwann, the theory was modified to include the idea that all cells arise from pre-existing cells.

### Step 3: Analyze the Options
- A. Slytherin: Not a scientist associated with cell theory.
- B. Brown: Known for the discovery of the nucleus but did not modify the cell theory.
- C. Schwann: He is credited with the first modification in 1839 when he stated that all animal tissues are made up of cells.
- D. Grew: Not directly associated with the modification of the cell theory.

### Step 4: Conclusion
Since Schwann was the first to modify the cell theory by stating that all animal tissues are made up of cells, the correct answer is **C. Schwann**.

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