Under the unfavourable condition, the Amoeba withdraws its pseudopodia and secretes a three-layered hard covering or cyst around itself . This phenomenon is termed as

Options

A. Binary fission
B. Sporulation
C. Budding
D. Encystation

Answer

To solve the question regarding the phenomenon in which Amoeba withdraws its pseudopodia and secretes a three-layered hard covering or cyst around itself under unfavorable conditions, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**:
- The question describes a behavior of Amoeba in response to unfavorable environmental conditions. This behavior involves the formation of a protective covering.

2. **Analyzing the Options**:
- **Binary Fission**: This is a method of asexual reproduction where a single organism divides into two parts. This option is not relevant to the formation of a protective covering.
- **Sporulation**: This refers to the process of forming spores, which is a dormant form of bacteria. This is also not applicable to Amoeba's behavior.
- **Budding**: This is another form of asexual reproduction where a new organism develops from a part of the parent organism. This does not involve the formation of a cyst.
- **Encystment**: This is the process where an organism forms a cyst, which is a protective structure, especially under unfavorable conditions.

3. **Identifying the Correct Answer**:
- Among the given options, **encystment** is the correct term that describes the phenomenon where Amoeba withdraws its pseudopodia and secretes a hard covering or cyst around itself.

4. **Conclusion**:
- Therefore, the correct answer to the question is **encystment**.

### Final Answer:
The phenomenon is termed as **encystment**.