Which is absent in bacteria

Options

A. Cell wall
B. Mesosomes
C. Mitochondria
D. RNA.

Answer

To answer the question "Which is absent in bacteria?" we will analyze the options provided one by one.

### Step-by-Step Solution:

1. **Understanding Bacteria**:
- Bacteria are classified as prokaryotes, which means they lack a true nucleus and membrane-bound organelles.

2. **Analyzing the Options**:
- **Option A: Cell Wall**:
- Bacteria have a cell wall made of peptidoglycan. Therefore, this option is incorrect as cell walls are present in bacteria.

- **Option B: Mesosomes**:
- Mesosomes are invaginations of the plasma membrane in bacteria that assist in respiration and cell division. Thus, mesosomes are also present in bacteria, making this option incorrect.

- **Option C: Mitochondria**:
- Mitochondria are membrane-bound organelles found only in eukaryotic cells. Since bacteria are prokaryotes, they do not have mitochondria. Therefore, this option is correct as mitochondria are absent in bacteria.

- **Option D: RNA**:
- RNA is present in bacteria. Although their genetic material is primarily DNA, various forms of RNA (like tRNA and rRNA) are essential for protein synthesis. Hence, this option is incorrect.

3. **Conclusion**:
- Based on the analysis, the correct answer to the question "Which is absent in bacteria?" is **Mitochondria**.

### Final Answer:
**Mitochondria are absent in bacteria.**

---