Thermal pollution is caused by

Options

A. Power plants
B. Industries
C. Automobiles
D. All of the above

Answer

### Step-by-Step Text Solution

1. **Understanding Thermal Pollution**:
- Thermal pollution refers to the degradation of water quality by any process that changes ambient water temperature. It is primarily associated with the discharge of heated water into natural water bodies.

2. **Causes of Thermal Pollution**:
- Thermal pollution can arise from various sources, including:
- **Power Plants**: These facilities use water as a coolant to regulate temperature during energy production. After cooling, the heated water is often discharged back into nearby rivers or lakes, raising the water temperature and affecting aquatic ecosystems.
- **Industrial Processes**: Similar to power plants, many industries utilize water for cooling purposes. The heated water released back into the environment can lead to thermal pollution.
- **Automobiles**: Vehicles emit greenhouse gases that contribute to global warming. Increased atmospheric temperatures can indirectly raise the temperature of nearby water bodies, leading to thermal pollution.

3. **Effects of Thermal Pollution**:
- The increase in water temperature can lead to:
- Decreased levels of dissolved oxygen in the water, which is critical for aquatic life.
- Altered species composition and loss of biodiversity in aquatic ecosystems.

4. **Conclusion**:
- Therefore, thermal pollution is caused by multiple factors, including power plants, industrial activities, and automobiles. All these sources contribute to the rise in water temperatures, leading to detrimental effects on aquatic life.

### Final Answer:
Thermal pollution is caused by all of the above (power plants, industrial processes, and automobiles).

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