What do decomposing organisms need in order to turn into fossil fuels (over hundreds of millions of years)?

After the plant material turns into peat, it is buried by sediment. Over millions of years, the pressure from above and heat from the earth squeeze and evaporate any residual moisture from the peat and it is transformed into coal.

Explanation:

After the plant material turns into peat, it is buried by sediment. Over millions of years, the pressure from above and heat from the earth squeeze and evaporate any residual moisture from the peat and it is transformed into coal.

Fossil fuel is a general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years

Explanation:

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.