Schleiden and Schwann proposed cell theory in

Options

A. 1836-37
B. 1838-39
C. 1901-02
D. 1938-39

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the time period when Schleiden and Schwann proposed the cell theory.

2. **Identifying the Scientists**: The two scientists involved are Matthias Schleiden and Theodor Schwann.

3. **Researching Schleiden's Contribution**: Matthias Schleiden, in the year 1838, stated that all plant tissues are composed of cells, emphasizing that cells are the basic structural unit of life.

4. **Researching Schwann's Contribution**: Theodor Schwann, in the year 1839, extended this idea to animal tissues, asserting that all animal tissues are also made up of cells. He highlighted that cells are the fundamental units of both structure and function in living organisms.

5. **Combining Their Contributions**: Together, Schleiden's and Schwann's findings led to the formulation of the cell theory, which posits that all living organisms are composed of cells, and that the cell is the basic unit of life.

6. **Choosing the Correct Option**: Based on the years of their contributions, the correct answer to the question is option B: 1838-39.

**Final Answer**: The cell theory was proposed by Schleiden and Schwann in 1838-39 (Option B).

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