Plant material (leaves, stems, trunks) in oxygen-poor swamps are buried for a geologically long time. The result is coal (Option b).
What is coal?
Coal is a combustible formed as rocks (coal seams), which are composed of organic matter rich in carbon.
Coal is a type of fossil combustible because it is composed of fossilized plants (carbonized plants) on the Earth's crust.
Fossils are dead organisms (e.g., dead plants and dead animals) that once lived on the Earth planet.
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