Pollution is

Options

A. removal of topsoil
B. release of toxic/undesirable materials in environment
C. conservation of energy
D. All of the above

Answer

### Step-by-Step Solution

1. **Understanding Pollution**:
- Pollution is defined as the introduction of harmful materials into the environment. These materials can be in the form of chemicals, waste, or other substances that negatively impact air, water, and soil quality.

2. **Analyzing the Options**:
- **Option 1: Removal of topsoil**: This refers to soil erosion, which is a process that can lead to land degradation but is not directly defined as pollution.
- **Option 2: Release of toxic undesirable materials in the environment**: This option accurately describes pollution, as it involves harmful substances that contaminate the environment.
- **Option 3: Conservation of energy**: This is not a type of pollution. In fact, conserving energy is beneficial for the environment and helps reduce pollution.
- **Option 4: All of these**: Since options 1 and 3 do not describe pollution, this option cannot be correct.

3. **Conclusion**:
- The correct answer is **Option 2**, which states that pollution involves the release of toxic or undesirable materials into the environment.