The smallest organisms without any specific shape and cell wall, which cause diseases among plants are

Options

A. chlamydia
B. fungi
C. mycoplasma
D. bacteria

Answer

To solve the question, "The smallest organisms without any specific shape and cell wall, which cause diseases among plants are," we will analyze the options provided.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are Chlamydia, Fungi, Mycoplasma, and Bacteria.

2. **Understand the Characteristics of Each Option**:
- **Chlamydia**: This is a type of bacteria that has a cell wall.
- **Fungi**: These are eukaryotic organisms that have a defined shape and a cell wall made of chitin.
- **Mycoplasma**: These are the smallest known microorganisms that lack a cell wall and do not have a specific shape.
- **Bacteria**: Most bacteria have a cell wall made of peptidoglycan and possess a defined shape.

3. **Evaluate the Characteristics**:
- We are looking for the smallest organisms that do not have a cell wall and do not have a specific shape.
- Mycoplasma fits this description as they are indeed the smallest microorganisms and lack a cell wall, which means they do not have a definite shape.

4. **Conclusion**: Based on the analysis, the correct answer is **Mycoplasma**. These organisms are pathogenic and can cause diseases in both plants and animals.

### Final Answer:
The smallest organisms without any specific shape and cell wall, which cause diseases among plants are **Mycoplasma**.