What are pathogenic microorganisms?

Explanation

### Step-by-Step Solution:

1. **Definition of Pathogenic Microorganisms**: Pathogenic microorganisms are organisms that have the ability to cause diseases in other living beings, including humans.

2. **Characteristics**: These microorganisms are typically very small and cannot be seen with the naked eye. They require a microscope to be observed.

3. **Types of Pathogenic Microorganisms**: Pathogenic microorganisms can include various types of organisms, such as bacteria, viruses, fungi, and protozoa.

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