water eroding the land. meteors hitting Earth. repeated volcanic eruptions. the decay of organic material.
I gave my students this multiple choice question: Coal is a fossil fuel that is formed from

Only one answer is correct among these 4 choices:
- water eroding the land.
- meteors hitting Earth.
- repeated volcanic eruptions.
- the decay of organic material.

Could you tell me which one is correct?

the decay of organic material.