What are the major groups of microorganisms?

Explanation

**Step-by-Step Solution:**

1. **Definition of Microorganisms**: Microorganisms are tiny living organisms that cannot be seen with the naked eye. They require a microscope or magnifying lens for observation.

2. **Diversity of Microorganisms**: Microorganisms vary in size, structure, and habitat. They can be found in different environments and can have various roles, including beneficial and harmful effects.

3. **Major Groups of Microorganisms**:
- **Bacteria**:
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