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Crude oil is a finite resource. Petrol and other fuels are produced from it using fractional distillation and cracking. Combustion products may cause environmental and health problems.

There is evidence that the Earth's early atmosphere contained less oxygen but more carbon dioxide and water vapour than it does today. Increased emissions of greenhouse gases have led to climate change.

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.