HOW is there so much crude oil left?

Question

In grade school I remember learning that the creation of crude oil in the Earth’s crust was a rare event. How was so much created?

In: 19

Answer 1

Back in the day, there were lots of living things that no other living things really knew how to eat. As such, when those things died, they got buried underground. This was the case for a loooooong time, so there were lots of dead things that got buried.

These dead things were the source of the hydrocarbons we use now.