Which of the following is not a fossil fuel used as a conventional energy source?

Introduction / Context:
This question comes from general science and environmental studies. It asks you to identify which listed energy source is not a fossil fuel. Understanding the difference between fossil fuels and other energy sources is important for topics such as pollution, climate change, and non conventional energy.

Given Data / Assumptions:
- The options include natural gas, uranium, coal, and petroleum. - Fossil fuels are formed from ancient organic matter. - The question asks for the option that does not belong to the fossil fuel category.

Concept / Approach:
Fossil fuels such as coal, petroleum, and natural gas are formed over millions of years from the remains of plants and animals under high pressure and temperature. Uranium, however, is a radioactive element used as fuel in nuclear reactors. It is not formed from ancient organic matter and therefore is not classified as a fossil fuel.

Step-by-Step Solution:
1. Recall that coal is a fossil fuel obtained from ancient plant material. 2. Petroleum and natural gas are fossil fuels formed from marine organisms and organic deposits. 3. Uranium is a naturally occurring radioactive metal mined from ore deposits. 4. Uranium provides nuclear energy through fission, not chemical combustion. 5. Therefore, uranium is not a fossil fuel, while the others are.

Verification / Alternative check:
Energy resources chapters in school science books clearly list coal, petroleum, and natural gas as fossil fuels, whereas uranium is always discussed under nuclear energy. This confirms the classification.

Why Other Options Are Wrong:
Natural gas: A fossil fuel mainly composed of methane, formed from decomposed organic matter. Coal: A solid fossil fuel formed from compressed plant material. Petroleum: A liquid fossil fuel, also called crude oil, derived from ancient marine organisms.

Common Pitfalls:
Students sometimes confuse all non renewable resources with fossil fuels. Nuclear fuel such as uranium is non renewable on human time scales but is not a fossil fuel. Always remember that fossil fuels originate from fossilized biological material.

Final Answer:
The energy source that is not a fossil fuel is Uranium.