The undesirable material that enters into the environment by natural source or due to human activity is called _______

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a term that describes undesirable materials entering the environment from both natural sources and human activities.

2. **Identifying Key Concepts**:
- **Undesirable materials**: These are substances that can harm the environment or living organisms.
- **Sources**: These can be natural (like volcanic eruptions, wildfires) or anthropogenic (human activities such as industrial discharge, vehicle emissions).

3. **Recalling Relevant Terminology**: In environmental chemistry, the term used to describe such undesirable materials is "pollutants."

4. **Types of Pollutants**:
- **Air Pollutants**: Substances that contaminate the air, such as carbon dioxide, sulfur dioxide, and nitrogen dioxide.
- **Water Pollutants**: Contaminants that affect water bodies, which can include chemicals, waste, and pathogens.

5. **Conclusion**: Therefore, the answer to the question is that the undesirable material that enters into the environment by natural sources or due to human activity is called **pollutants**.

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