What in air is needed for coal to burn?

Related questions

• What are some examples of carbon sources and carbon sinks?
• Why are fossil fuels bad?
• How do fossil fuels form?
• Why did the plants and animals that make up fossil fuels not rot away?
• What plants and animals make up fossil fuels?
• How do fossil fuels differ from other fuels?
• What are the pros and cons of fossil fuels?
• Why are fossil fuels harmful for the environment?
• What might replace fossil fuels in the future?
• What are some examples of fossil fuels?