Cells of many protists, plants, and fungi, but not animals, commonly have :

Options

A. cell wall
B. ribosomes
C. plasma membrane
D. mitochondria

Explanation

To answer the question regarding what cells of many protists, plants, and fungi commonly have, but not animals, we can analyze the options provided:

### Step-by-Step Solution:

1. **Understanding Cell Structures**:
- We need to consider the basic structures found in various types of cells.
- Cells can have different components, and we are looking for a feature that is present in protists, plants, and fungi, but absent in animal cells.

2. **Analyzing Option 1: Cell Wall**:
- The cell wall is a rigid outer layer that provides structural support and protection to the cell.
- It is commonly found in plants, fungi, and many protists (like algae).
- Animal cells do not have a cell wall; they only have a plasma membrane.

3. **Analyzing Option 2: Ribosomes**:
- Ribosomes are essential for protein synthesis and are found in all types of cells, including animal cells.
- Therefore, ribosomes cannot be the correct answer as they are present in animals as well.

4. **Analyzing Option 3: Plasma Membrane**:
- The plasma membrane is a fundamental structure present in all cells, including animal cells.
- Since this structure is not exclusive to protists, plants, and fungi, it cannot be the correct answer.

5. **Analyzing Option 4: Mitochondria**:
- Mitochondria are known as the powerhouses of the cell and are involved in energy production.
- They are present in both plant and animal cells, thus making this option incorrect as well.

6. **Conclusion**:
- After analyzing all the options, the only structure that is present in protists, plants, and fungi but not in animals is the **cell wall**.

### Final Answer:
The correct answer is **cell wall**.