coal is made mostly of skeletal remains of animals. coal is formed from magma that has solidified over time. it quickly becomes petrified when water is removed. geologic processes continue over millions of years.
I gave my students this multiple choice question: Coal is solid rock that began as organic material that was deposited in a swamp. The formation of coal suggests that

Only one answer is correct among these 4 choices:
- coal is made mostly of skeletal remains of animals.
- coal is formed from magma that has solidified over time.
- it quickly becomes petrified when water is removed.
- geologic processes continue over millions of years.

Could you tell me which one is correct?

geologic processes continue over millions of years.