Resources

1. Fossil fuel

1.1. Petroleum

1.1.1. Occurrence

1.1.2. Formation

1.1.3. Extraction

1.1.4. Refining

1.1.5. Uses

1.2. Coal

1.2.1. Formation

1.2.2. Product

1.2.2.1. Coal gas

1.2.2.2. Coal tar

1.2.2.3. Coke

1.3. Natural gas

1.3.1. Advantage

1.3.2. Uses

1.4. Petrochemical

1.4.1. Energy resources are limited

1.4.2. Saving petrol and diesel

2. Natural resources

2.1. Exhaustible resources

2.1.1. Exhaustible resources

2.2. New Topic