All living beings are composed of ______ ?

Options

A. Cells and product of cells
B. Cells only
C. Product of cells only
D. Nucleus only

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks what all living beings are composed of. This requires knowledge of the fundamental unit of life.

2. **Identifying the Fundamental Unit**: All living organisms are made up of cells. Cells are often referred to as the "building blocks" of life.

3. **Explaining Cell Composition**: Cells themselves are composed of various components, including protoplasm, which contains the nucleus and other organelles.

4. **Referencing Cell Theory**: According to the cell theory, all living organisms are composed of cells and their products. This theory emphasizes that cells are the basic unit of structure and function in living things.

5. **Evaluating the Options**:
- **Option 1**: Cells and products of cells - This is correct as it includes both cells and their components.
- **Option 2**: Cells only - This is incorrect because it does not account for the products of cells.
- **Option 3**: Products of cells only - This is incorrect as it excludes the cells themselves.
- **Option 4**: Nucleus only - This is incorrect because it is just one part of the cell.

6. **Conclusion**: The correct answer is that all living beings are composed of **cells and products of cells**.

### Final Answer:
All living beings are composed of **cells and products of cells**.

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