Coal is solid rock that began as organic material that was deposited in a swamp. the formation of coal suggests that a. geologic processes continue over millions of years. b. coal is made mostly of skeletal remains of animals. c. coal is formed from magma that has solidified over time. d. it quickly becomes petrified when water is removed.

A. Geological processes continue over millions of years.  

A swamp is a wetland which exhibit the growth of vegetation. It consist of vegetation which is being dominated by trees. When these trees die, the wooden parts sank below the water. The wood remains being deposited at the bottom of the water body causes the formation of coal. Coal formation results due to the wood being compressed and buried. It takes millions of years for the transformation of wood into coal in the geosphere of the swamp region.

Hence, formation of coal is a geological process and it takes millions of years for it's formation.

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