What is biotic index?

Explanation

### Step-by-Step Solution:

1. **Definition of Biotic Index**: The biotic index is a scale used to assess the quality of an environment, particularly focusing on the presence and types of organisms within that environment.

2. **Purpose of Biotic Index**: It serves to indicate the health of an ecosystem, primarily by analyzing the types of organisms present in a given area. This is especially relevant in aquatic environments.

3. **Application in Water Quality Assessment**: The biotic index is most commonly used to evaluate water quality. This is done by collecting water samples from a specific location.

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