The contamination of environment by unwanted substances is known as ____________

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes the contamination of the environment by unwanted substances.

2. **Identifying Key Terms**: The key terms in the question are "contamination," "environment," and "unwanted substances."

3. **Defining Contamination**: Contamination refers to the introduction of harmful or unwanted substances into the environment.

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