Understanding Fossil Sources of Energy
Fossil sources of energy refer to energy derived from the remains of ancient plants and animals that have undergone natural processes over millions of years. Among the options provided, petroleum is the only fossil fuel.

Why Petroleum is a Fossil Source
- Origin: Petroleum is formed from the decomposed remains of marine organisms. Over millions of years, heat and pressure transform these organic materials into hydrocarbons, which constitute crude oil.
- Combustion: When burned, petroleum releases energy, making it a significant source of fuel for transportation, heating, and electricity generation.
- Non-renewable: Fossil fuels like petroleum are considered non-renewable resources since their formation takes millions of years, and their reserves are limited.

Comparison with Other Options
- Wood: Although wood can be considered a source of energy, it is classified as biomass energy. It is renewable as trees can be replanted and regrown.
- Solar Radiation: Solar energy is a renewable energy source harnessed from the sun. It does not involve the combustion of fossilized organic matter.
- Tidal Waves: Tidal energy comes from the gravitational pull of the moon and sun on Earth’s oceans. It is also a renewable source, not derived from fossilized remains.

Conclusion
In summary, petroleum is the correct answer as it is a fossil source of energy, while wood, solar radiation, and tidal waves represent renewable energy sources. Understanding these distinctions is essential for evaluating energy sources in terms of sustainability and environmental impact.