What is is it like? (form)

Petroleum is used more than any other substance in the world. Some petroleum fuels are used to generate heat and power. petroleum can pollute. Oil and natural gas are both types of petroleum. Oil is the liquid form and natural gas is the gaseous form. Coal looks like rock but it was once a living organism. Fossil fuels are non-renewble recources. Petroleum is a natural gas. It is oil found in the ground, it can be as thick as tar or as thin as water. Propane is what we use to power our grills. Propane is not like a natural gas. You can't see it, smell or taste it? Propane is a clean fuel that is very portablt. Coal is black or brown. Gsas, coal and oil are common fuels.