Microorganisms found in:

Options

A. deserts
B. marshy lands
C. hotsprings
D. All of these

Explanation

### Step-by-Step Solution:

1. **Definition of Microorganisms**: Microorganisms are tiny living organisms that cannot be seen with the naked eye and require a microscope for observation. They include bacteria, viruses, pathogens, and protozoans.

2. **Habitat of Microorganisms**: Microorganisms can thrive in a variety of environments, including extreme conditions. They are adaptable and can be found in places with high temperatures, high pH levels, and high pressure.

3. **Examples of Environments**:
- **Deserts**: Despite the harsh conditions and high temperatures, certain microorganisms can survive in deserts.
- **Marshy Lands**: These areas often have high salt concentrations, yet microorganisms are still present.
- **Hot Springs**: These environments can reach temperatures of around 200 degrees Celsius, and microorganisms known as extremophiles thrive in such heat.

4. **Conclusion**: Microorganisms are ubiquitous and can be found in a wide range of environments, from deserts to marshy lands and hot springs. They are resilient and can adapt to extreme conditions.

### Final Answer:
Microorganisms are found in various environments including deserts, marshy lands, and hot springs. They can survive in extreme conditions such as high temperatures, high salinity, and high pressure.

---