Which of the following is the structural and functional unit of all living organism?

Options

A. Chloroplast
B. Matter
C. Water
D. Cell

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the structural and functional unit of all living organisms. This means we need to identify what the basic building block of life is.

2. **Analyzing the Options**:
- **Option 1: Chloroplast**: This is an organelle found in plant cells that is responsible for photosynthesis. While important, it is not the basic unit of life.
- **Option 2: Matter**: Matter refers to anything that has mass and takes up space. It is not a unit of life.
- **Option 3: Water**: Water is essential for life and is involved in many biological processes, but it is not a structural or functional unit.
- **Option 4: Cell**: A cell is the smallest unit of life that can function independently and perform all necessary life processes.

3. **Identifying the Correct Answer**: After analyzing all the options, it is clear that the cell is the basic structural and functional unit of all living organisms.

4. **Conclusion**: Therefore, the correct answer to the question is **Cell**.