Monerans devoid of a wall are

Options

A. Actinomycetes
B. Cyanobacteria
C. Mycoplasma
D. Eubacteria.

Answer

To answer the question "Monerans devoid of a wall are," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Monera**:
- The kingdom Monera consists of prokaryotic organisms, which are unicellular and lack a true nucleus. They are characterized by the absence of membrane-bound organelles.

2. **Identifying the Characteristics of Monerans**:
- Monerans typically have a cell wall, which is a common feature among many bacteria. However, there are exceptions in this kingdom.

3. **Analyzing the Options**:
- The options provided are:
- Option 1: Actinomycetes
- Option 2: Cyanobacteria
- Option 3: Mycoplasma
- Option 4: Eubacteria

4. **Evaluating Each Option**:
- **Actinomycetes**: These are a group of bacteria that do have a cell wall.
- **Cyanobacteria**: These are photosynthetic bacteria that also possess a cell wall.
- **Mycoplasma**: This is a genus of bacteria known for lacking a cell wall. They are unique among prokaryotes in that they do not have a rigid cell wall structure.
- **Eubacteria**: This term generally refers to true bacteria, which typically possess a cell wall.

5. **Conclusion**:
- Based on the analysis, the only option that represents monerans devoid of a cell wall is **Mycoplasma**. Therefore, the correct answer is **Option 3: Mycoplasma**.