The origin of crude oil
1 mark · EasyState how long it takes for crude oil to form from the remains of sea plants and animals.
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Millions of years
Also accept: Many millions of years; A very long time; Over millions of years
Common mistakes: Thousands of years; Hundreds of years
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Marking points
B1 · 1 mark · States that crude oil forms over millions of years
Worked solution
Crude oil forms over millions of years.