Smallest wall-less monerans

Options

A. Develop fried egg appearance in culture
B. Are motile
C. Have definite shape
D. Are mostly saprophytic

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the smallest wall-less monerans. Monerans refer to prokaryotic organisms, which include bacteria and similar entities.

2. **Identifying Wall-less Monerans**: The smallest wall-less monerans are known as mycoplasmas. They are unique because they lack a cell wall, which is a characteristic feature of most bacteria.

3. **Characteristics of Mycoplasma**:
- **Cell Wall Absence**: Mycoplasmas do not have a cell wall, which makes them flexible and able to change shape.
- **Size**: They are among the smallest known bacteria, often measuring around 0.1 to 0.3 micrometers in diameter.
- **Shape**: Mycoplasmas do not have a definite shape; they can appear as spherical, filamentous, or even branched forms.
- **Motility**: Mycoplasmas are generally non-motile as they lack flagella.
- **Nutritional Mode**: While some mycoplasmas can be saprophytic, most are parasitic, living off a host organism.

4. **Analyzing the Options**:
- The question provides options related to mycoplasmas. The correct statement about mycoplasmas is that they develop a "fried egg" appearance when cultured, which is a characteristic feature observed in laboratory conditions.

5. **Conclusion**: The smallest wall-less monerans are mycoplasmas, which are characterized by their lack of a cell wall, non-motility, and the ability to appear like fried eggs in culture.

### Final Answer:
The smallest wall-less monerans are **mycoplasmas**.

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