Identify the correct explanation of mesosome. It is

Options

A. A specialised structure of prokaryotic cell formed by extension of plasma membrane into the cytoplasm
B. The middle layer of prokaryotic cell wall
C. The organelle of eukaryotic cell
D. The middle layer of eukaryotic cell wall.

Answer

### Step-by-Step Solution

1. **Understanding Mesosomes**: Mesosomes are specialized structures found in prokaryotic cells (like bacteria). They are formed by the infolding of the plasma membrane.

2. **Function of Mesosomes**: The primary function of mesosomes is to increase the surface area of the cell. This increase in surface area is crucial for enhancing cellular processes, particularly cellular respiration in bacteria.

3. **Analyzing the Options**: The question provides four options regarding the explanation of mesosomes. We need to identify which option correctly describes them.

4. **Identifying the Correct Option**:
- The first option states that mesosomes are a specialized structure of prokaryotic cells formed by the extension of the plasma membrane into the cytoplasm. This description accurately reflects what mesosomes are and their formation process.
- The other options may not correctly describe mesosomes or may include incorrect information.

5. **Conclusion**: Based on the analysis, the correct explanation of mesosomes is that they are specialized structures formed by the infolding of the plasma membrane in prokaryotic cells, which serve to increase surface area for cellular respiration.

### Final Answer
The correct explanation of mesosomes is: "A specialized structure of prokaryotic cell formed by extension of plasma membrane into the cytoplasm."