Under unfavourable conditions, Amoeba produces a three-layered structure. to tide over the unfavourable environmental conditionsThe phenomenon is

Options

A. Sporulation
B. Encystment
C. Conjugation
D. Regeneration.

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question asks about the phenomenon in which Amoeba produces a three-layered structure under unfavorable conditions. This structure helps the organism survive until conditions improve.

2. **Identifying the Structure**: The three-layered structure produced by Amoeba is known as a cyst. This cyst is formed to protect the organism from harsh environmental conditions.

3. **Explaining the Process**: When conditions become unfavorable, Amoeba decreases its metabolic activity and encases itself in this cyst. The cyst has a tough outer wall that prevents desiccation (drying out) and decay.

4. **Recognizing the Term**: The process of forming this protective cyst is referred to as "insistment." This term specifically describes the formation of a cyst in response to adverse conditions.

5. **Releasing Amoeba**: Once favorable conditions return, the Amoeba can undergo multiple fission within the cyst, producing several daughter nuclei. Eventually, the cyst ruptures, releasing the young Amoebae.

6. **Conclusion**: Therefore, the phenomenon where Amoeba produces a three-layered structure to survive unfavorable conditions is called "insistment."

**Final Answer**: The phenomenon is called "insistment."

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