CLEAN : FILE: Angola's President Dos Santos to stand down in 2017: state

What is the basic definition of burning?

• A physical change in state

• A process of cooling down materials

• A chemical reaction involving oxygen

• A method of freezing substances

Which element is crucial for the burning process?

• Carbon

• Oxygen

• Nitrogen

• Hydrogen

What happens to substances during the burning process?

• They become colder

• They gain electrons

• They dissolve in water

• They release energy

In which industry is burning a critical process?

• Automobile

• Textile

• Food

• Construction

How does burning impact the environment?

• It reduces air pollution

• It has no impact

• It increases oxygen levels

• It contributes to air pollution