Unfavorable environmental conditions such as lack of nutrients or oxygen, extreme temperatures, lack of moisture and presence of toxic chemicals, which are not conducive for the growth of the microbe trigger the formation of a cyst.

Formation of a Cyst in Microorganisms
Cysts are protective structures formed by some microorganisms to survive in unfavorable conditions. Let's delve into why cysts are formed in some microorganisms:

Survival Mechanism
- Cysts serve as a survival mechanism for microorganisms when they encounter harsh environmental conditions such as extreme temperatures, lack of nutrients, or presence of toxic substances.
- By forming cysts, microorganisms can remain dormant until conditions become favorable for their growth and reproduction.

Protection from Desiccation
- Cysts provide protection from desiccation, which is the process of drying out. This is crucial for microorganisms living in environments where water availability fluctuates.

Resistance to Harsh Conditions
- The thick walls of cysts offer protection against various environmental stressors, including UV radiation, chemicals, and predators.
- Inside the cyst, the microorganism can remain viable for extended periods without the need for nutrients or other resources.

Enhanced Survival Rate
- By forming cysts, microorganisms increase their chances of survival in challenging conditions, ensuring the continuity of their species.
In conclusion, the formation of cysts in some microorganisms is a remarkable adaptation that allows them to withstand adverse environmental conditions and ensure their survival.