Which one of the following prokaryotes lack cell wall?

Options

A. Virus
B. Cyanobacteria
C. Mycoplasma
D. Protozoa

Answer

### Step-by-Step Solution:

1. **Understanding Prokaryotes**: Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and organelles. They typically have a cell wall that provides structure and protection.

2. **Identifying the Options**: The options provided are:
- Virus
- Cyanobacteria
- Mycoplasma
- Protozoa

3. **Analyzing Each Option**:
- **Virus**: Viruses are not considered prokaryotes as they are acellular and do not have a cell wall.
- **Cyanobacteria**: Cyanobacteria are prokaryotic organisms that possess a cell wall made of peptidoglycan.
- **Mycoplasma**: Mycoplasma are a group of bacteria that are unique because they lack a cell wall. They are the smallest known living bacteria.
- **Protozoa**: Protozoa are eukaryotic organisms and do not fall under the category of prokaryotes.

4. **Conclusion**: Among the options, Mycoplasma is the only prokaryote that lacks a cell wall. Therefore, the correct answer is **Mycoplasma**.