Where does crude oil come from?

I have a gcse tomorrow and i was wondering where crude oil came from. I said the earths crust and my friend said the sea, please can you tell me which is right.. Thanks :)

One Response to “Where does crude oil come from?”

  1. G$Money Says:

    Crude oil comes from dead tropical plants from the time when the earth still had supercontinents like pangea, so crude oil can be found almost anywhere there was tropical plants